As filed with the Securities and Exchange Commission on December 7, 2018

Registration No. 333-          

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Boardwalk Pipeline Partners, LP

Boardwalk Pipelines, LP

(Exact name of registrants as specified in its charter)

9 Greenway Plaza, Suite 2800

Houston, Texas 77046

(866) 913-2122

(Address, including zip code, and telephone number, including area code, of registrants’ principal executive offices)

Michael E. McMahon

9 Greenway Plaza, Suite 2800

Houston, Texas 77046

(866) 913-2122

(Name, address, including zip code, and telephone number, including area code, of agent for service)

with a copy to:

E. Ramey Layne

James R. Brown

Vinson & Elkins L.L.P.

1001 Fannin Street, Suite 2500

Houston, Texas 77002

(713) 758-4629

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement as determined by market conditions and other factors.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box:  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box:  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.    Yes  ☐    No  ☐

CALCULATION OF REGISTRATION FEE

The Registrants hereby amend this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrants shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to completion, dated December 7, 2018.

PROSPECTUS

Boardwalk Pipeline Partners, LP

Boardwalk Pipelines, LP

Debt Securities

Warrants

Rights

Fully and Unconditionally Guaranteed by

Boardwalk Pipeline Partners, LP

Boardwalk Pipelines, LP, may, in one or more offerings and in one or more series, offer and sell (i) its debt securities, which may be fully and unconditionally guaranteed by us, and may also be guaranteed by one or more of our subsidiaries, (ii) warrants to purchase its debt securities and (iii) rights to purchase its debt securities, in amounts, at prices and on terms to be determined by market conditions and other factors at the time of our offerings. We will provide information in the related prospectus supplement for the trading market, if any, for any debt securities Boardwalk Pipelines, LP may offer.

We may offer the securities in amounts, at prices and on terms to be determined by market conditions and other factors at the time of the offer. This prospectus describes only the general terms of these securities and the general manner in which we will offer the securities. The specific terms of any securities that we offer will, if not included in this prospectus or information incorporated by reference herein, be included in a supplement to this prospectus. The prospectus supplement will describe the specific manner in which we will offer the securities, and also may add, update or change information contained in this prospectus. We may sell these securities through underwriters on a firm commitment basis. The names of any underwriters and the specific terms of a plan of distribution will be stated in a supplement to this prospectus.

You should read this prospectus and any applicable prospectus supplement and the documents incorporated by reference herein or therein carefully before you invest in any of our securities. You should also read the documents we have referred you to in the “Where You Can Find More Information” and “Information We Incorporate by Reference” sections of this prospectus for information about us, including our financial statements. This prospectus may not be used to consummate sales of our securities unless it is accompanied by a prospectus supplement.

Investing in our securities involves a high degree of risk. You should carefully consider each of the factors referred to under “Risk Factors” beginning on page 3 of this prospectus and contained in the applicable prospectus supplement and in the documents incorporated by reference herein and therein before you make an investment in our securities.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

THE DATE OF THIS PROSPECTUS IS                , 2018.

TABLE OF CONTENTS

In making your investment decision, you should rely only on the information contained in this prospectus, any prospectus supplement and the documents we have incorporated by reference in this prospectus. We have not authorized anyone else to give you different information. We are not offering these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front of those documents. We will disclose any material changes in our affairs in an amendment to this prospectus, a prospectus supplement or a future filing with the SEC incorporated by reference in this prospectus.

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we have filed with the SEC using a “shelf” registration process. Under this shelf registration process, we may offer and sell, in one or more offerings, up to $1,000,000,000 of the securities described in this prospectus. Each time we offer securities with this prospectus, we will provide you with a prospectus supplement that will describe, among other things, the specific amounts, types and prices of the securities being offered and the terms of the offering. Any prospectus supplement may also add to, update or change information contained or incorporated by reference in this prospectus. Any statement that we make in or incorporate by reference in this prospectus will be modified or superseded by any inconsistent statement made by us in a prospectus supplement. Therefore, you should read this prospectus (including any documents incorporated by reference) and any attached prospectus supplement before you invest in our securities.

Unless the context clearly indicates otherwise, references in this prospectus to “Boardwalk,” “we,” “our,” “us” or similar terms refer to Boardwalk Pipeline Partners, LP and, unless the context indicates otherwise, its subsidiaries. References in this prospectus to our “general partner” refer to Boardwalk GP, LP and/or Boardwalk GP, LLC, the general partner of Boardwalk GP, LP, as appropriate. References to “Loews” refer to Loews Corporation, the ultimate parent company of our general partner. References to “BPHC” refer to Boardwalk Pipelines Holding Corp., a wholly owned subsidiary of Loews.

The information in this prospectus is accurate as of its date. You should not assume that the information contained in this prospectus is accurate as of any other date. You should read carefully this prospectus, any prospectus supplement, and the additional information described below under the heading “Where You Can Find More Information” and “Information We Incorporate by Reference.”

ABOUT BOARDWALK PIPELINE PARTNERS, LP

We are a limited partnership operating in the midstream portion of the natural gas and natural gas liquids industry, providing transportation and storage services for those commodities.

As of June 30, 2018, BPHC owned 125.6 million of the common units representing limited partner interests in us, and, through our general partner, an indirect wholly owned subsidiary of BPHC, held the 2% general partner interest in us and all of our incentive distribution rights. On July 18, 2018, our general partner purchased all of our issued and outstanding common units not already owned by our general partner and its affiliates. As a result of this transaction, we filed a Form 25 with the SEC to voluntarily withdraw our common units from listing on the New York Stock Exchange (“NYSE”) and from registration under Section 12(b) of the Securities Exchange Act of 1934. Our common units were traded on the NYSE through July 17, 2018, under the symbol “BWP.”

Our principal executive offices are located at 9 Greenway Plaza, Suite 2800, Houston, Texas, 77046, and our phone number is (866) 913-2122. Our website is located at http://www.bwpmlp.com. We make our periodic reports and other information filed with or furnished to the SEC available, free of charge, through our website, as soon as reasonably practicable. Information on our website or any other website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus unless specifically so designated and filed with the SEC.

ABOUT BOARDWALK PIPELINES, LP

Boardwalk Pipelines, LP is our wholly owned subsidiary. We have no operations other than through Boardwalk Pipelines, LP.

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WHERE YOU CAN FIND MORE INFORMATION

We have filed a registration statement with the SEC under the Securities Act that registers the offer and sale of the securities covered by this prospectus. The registration statement, including the attached exhibits, contains additional relevant information about us. The rules and regulations of the SEC allow us to omit some information included in the registration statement from this prospectus.

We file annual, quarterly and other reports and information with the SEC. Our SEC filings are available at the SEC’s web site at http://www.sec.gov which contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. You can also obtain information about us on our website at www.bwpmlp.com. Information on our website or any other website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus unless specifically so designated and filed with the SEC.

INFORMATION WE INCORPORATE BY REFERENCE

The SEC allows us to “incorporate by reference” the information we have filed with the SEC. This means that we can disclose important information to you without actually including the specific information in this prospectus by referring you to those documents. The information incorporated by reference is an important part of this prospectus. Information that we later provide to the SEC, and which is deemed to be “filed” with the SEC, will automatically update and may replace information in this prospectus and information previously deemed to be “filed” with the SEC.

The documents listed below and any future filings made by Boardwalk Pipeline Partners, LP with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (excluding those furnished to the SEC on Form 8-K), including all such documents we may file with the SEC after the date of the initial registration and prior to the effectiveness of the registration statement, are incorporated by reference in this prospectus, until the termination of each offering under this prospectus.

You may request a copy of any document incorporated by reference in this prospectus (excluding any exhibits to those documents, unless the exhibit is specifically incorporated by reference in this document), at no cost, by writing or calling us at the following address:

Boardwalk Pipeline Partners, LP

Attn: Public Relations

9 Greenway Plaza, Suite 2800

Houston, Texas 77046

(866) 913-2122

You should rely only on the information contained in or incorporated by reference in this prospectus or any prospectus supplement. We have not authorized anyone else to provide you with any information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information incorporated by reference or provided in this prospectus or any prospectus supplement is accurate as of any date other than its respective date.

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RISK FACTORS

An investment in the securities involves a significant degree of risk. Before you invest in the securities you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K, as supplemented by our Quarterly Reports on Form 10-Q and other subsequent filings to the extent applicable, each of which is incorporated herein by reference, and those risk factors that may be included in any applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference in evaluating an investment in the securities.

If any of the risks discussed in the foregoing documents were to occur, our business, financial condition, results of operations and cash flows could be materially adversely affected. In that case, we may be unable to pay interest on, or the principal of, any debt securities. In that event, the trading price of our securities could decline and you could lose all or part of your investment.

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FORWARD-LOOKING STATEMENTS AND ASSOCIATED RISKS

Some of the information contained in or incorporated by reference in this prospectus or in any prospectus supplement delivered with this prospectus, as well as some statements in periodic press releases and some oral statements made by our officials and our subsidiaries during presentations about us, may contain forward-looking statements. Forward-looking statements include, without limitation, any statement that may project, indicate or imply future results, events, performance or achievements, and may contain the words “expect,” “intend,” “plan,” “anticipate,” “estimate,” “believe,” “will likely result,” and similar expressions. In addition, any statement made by our management concerning future financial performance (including future revenues, earnings or growth rates), ongoing business strategies or prospects, and possible actions by our partnership or its subsidiaries, are also forward-looking statements. Forward-looking statements are based on current expectations and projections about future events and their potential impact on us. While management believes that these forward-looking statements are reasonable as and when made, there is no assurance that future events affecting us will be those that we anticipate. All forward-looking statements are inherently subject to a variety of risks and uncertainties, many of which are beyond our control, that could cause actual results to differ materially from those anticipated or projected. These risks and uncertainties include, among others:

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Developments in any of these areas could cause our results to differ materially from results that have been or may be anticipated or projected. When considering these forward-looking statements, you should keep in mind the risk factors and other cautionary statements in this prospectus or incorporated by reference herein, including those described in the “Risk Factors” section of our most recent Annual Report on Form 10-K and, to the extent applicable, our Quarterly Reports on Form 10-Q, other subsequent filings and any prospectus supplement. The risk factors and other factors noted in this prospectus, incorporated by reference herein or in any prospectus supplement delivered with this prospectus, as well as some statements in periodic press releases and some oral statements made by our officials and our subsidiaries during presentations about us, could cause our actual results to differ materially from those contained in any forward-looking statement.

Forward-looking statements speak only as of the date of this prospectus or, in the case of forward-looking statements contained in any document incorporated by reference, the date of such document, and we expressly disclaim any obligation or undertaking to update these statements to reflect any change in our expectations or beliefs or any change in events, conditions or circumstances on which any forward-looking statement is based.

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USE OF PROCEEDS

Except as otherwise provided in the applicable prospectus supplement, we will use the net proceeds (after the payment of offering expenses and underwriting discounts and commissions) we receive from the sale of the securities covered by this prospectus for general partnership purposes, including for the repayment of debt, to fund acquisitions and capital expenditures and additions to working capital.

The actual application of proceeds we receive from any particular offering of securities using this prospectus will be described in the applicable prospectus supplement relating to such offering.

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DESCRIPTION OF DEBT SECURITIES

The following description sets forth the general terms and provisions that apply to the debt securities. Each prospectus supplement will state the particular terms that will apply to the debt securities included in the supplement. The debt securities will be issued solely by Boardwalk Pipelines, LP, as the issuer. References in this “Description of Debt Securities” to “us,” “we,” or “our” refer only to Boardwalk Pipelines, LP, as issuer, and not to Boardwalk Pipeline Partners, LP or to any of Boardwalk Pipelines’ subsidiaries. References in this “Description of Debt Securities” to “the limited partnership” or “the guarantor” refer only to Boardwalk Pipeline Partners, LP, and not to any of its subsidiaries.

We will issue debt securities under one or more indentures among us, as issuer, The Bank of New York Mellon Trust Company, N.A., as trustee, and, if applicable, the limited partnership as guarantor. The debt securities will be governed by the provisions of the Indenture (as described below) and those made part of the Indenture by reference to the Trust Indenture Act of 1939. We, the Trustee and the guarantor, if applicable, may enter into supplements to the Indenture from time to time. If we decide to issue subordinated debt securities, we will issue them under a separate Indenture containing subordination provisions.

This description is a summary of the material provisions of the debt securities and the Indentures. We urge you to read the senior indenture and form of subordinated indenture filed as exhibits to the registration statement of which this prospectus is a part because those indentures, and not this description, govern your rights as a holder of debt securities. References in this prospectus to an “Indenture” refer to the particular indenture under which we issue a series of debt securities.

General

Debt Securities

Any series of debt securities that we issue:

The Indenture does not limit the total amount of debt securities that we may issue. We may issue debt securities under the Indenture from time to time in separate series, up to the aggregate amount authorized for each such series.

We will prepare a prospectus supplement and either an indenture supplement or a resolution of the board of directors of the limited partnership’s general partner and accompanying officers’ certificate relating to any series of debt securities that we offer, which will include specific terms relating to some or all of the following:

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This description of debt securities will be deemed modified, amended or supplemented by any description of any series of debt securities set forth in a prospectus supplement related to that series.

The prospectus supplement will also describe any material United States federal income tax consequences or other special considerations regarding the applicable series of debt securities, including those relating to:

At our option, we may make interest payments by check mailed to the registered holders of any debt securities or, if so stated in the applicable prospectus supplement, at the option of a holder by wire transfer to an account designated by the holder.

Unless otherwise provided in the applicable prospectus supplement, fully registered securities may be transferred or exchanged at the office of the Trustee at which its corporate trust business is principally administered in the United States, subject to the limitations provided in the Indenture, without the payment of any service charge, other than any applicable tax or governmental charge.

Any funds we pay to a paying agent for the payment of amounts due on any debt securities that remain unclaimed for two years will be returned to us, and the holders of the debt securities must look only to us for payment after that time.

The Guarantees

Our payment obligations under any series of debt securities may be jointly and severally, fully and unconditionally guaranteed by the limited partnership. If a series of debt securities is so guaranteed, the limited partnership will execute a notation of guarantee as further evidence of its guarantee. The applicable prospectus supplement will describe the terms of any guarantee by the limited partnership.

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If a series of debt securities is guaranteed by the limited partnership and is designated as subordinate to our senior indebtedness, then the guarantees by the limited partnership will be subordinated to the senior indebtedness of the limited partnership to substantially the same extent as the series is subordinated to our senior indebtedness. See “—Subordination.”

Covenants

The Indenture contains the following covenant for the benefit of the holders of all series of debt securities.

Reports

So long as any debt securities are outstanding, we will file with the Trustee, within 15 days after we or the limited partnership would have been required to file the same with the SEC, copies of the annual reports and of the information, documents and other reports that we or the limited partnership are required to file with the SEC pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 (the “Exchange Act”).

A series of debt securities may contain additional financial and other covenants. The applicable prospectus supplement will contain a description of any such covenants that are added to the Indenture specifically for the benefit of holders of a particular series.

Merger, Amalgamation, Consolidation and Sale of Assets

We will not merge, amalgamate or consolidate with or into any other person or sell, convey, transfer, lease or otherwise dispose of all or substantially all of our assets to any person, whether in a single transaction or series of related transactions, unless:

Thereafter, if we are not the surviving person, the surviving or transferee person will be substituted for us under the Indenture. If we sell or otherwise dispose of (except by lease) all or substantially all of our assets and the above stated requirements are satisfied, we will be released from all of our liabilities and obligations under the Indenture and the debt securities. If we lease all or substantially all of our assets, we will not be so released from our obligations under the Indenture and the debt securities.

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Events of Default, Remedies and Notice

Events of Default

Each of the following events will be an “Event of Default” under the Indenture with respect to a series of debt securities:

Exercise of Remedies

If an Event of Default, other than an Event of Default described in the fifth bullet point above, occurs and is continuing, the Trustee or the holders of at least 25% in principal amount of the outstanding debt securities of that series may declare the entire principal of, premium, if any, and accrued and unpaid interest, if any, on all the debt securities of that series to be due and payable immediately.

A default under the fourth bullet point above will not constitute an Event of Default until the Trustee or the holders of 25% in principal amount of the outstanding debt securities of that series notify us and, if the series of debt securities is guaranteed by the guarantor, the guarantor, of the default and such default is not cured within 60 days after receipt of notice (180 days in the case of a failure to comply with the covenant described under “—Covenants—Reports” above).

If an Event of Default described in the fifth bullet point above occurs and is continuing, the principal of, premium, if any, and accrued and unpaid interest on all outstanding debt securities of all series will become immediately due and payable without any declaration of acceleration or other act on the part of the Trustee or any holders.

The holders of a majority in principal amount of the outstanding debt securities of a series may:

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If an Event of Default occurs and is continuing, the Trustee will be under no obligation, except as otherwise provided in the Indenture, to exercise any of the rights or powers under the Indenture at the request or direction of any of the holders unless such holders have offered to the Trustee reasonable indemnity or security against any costs, liability or expense. No holder may pursue any remedy with respect to the Indenture or the debt securities of any series, except to enforce the right to receive payment of principal, premium, if any, or interest when due, unless:

The holders of a majority in principal amount of the outstanding debt securities of a series have the right, subject to certain restrictions, to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or of exercising any right or power conferred on the trustee with respect to that series of debt securities. The Trustee, however, may refuse to follow any direction that:

Notice of Event of Default

Within 30 days after the occurrence of an Event of Default, we are required to give written notice to the Trustee and indicate the status of the default and what action we are taking or propose to take to cure the default. In addition, we are required to deliver to the Trustee, on or before January 31 in each year, a compliance certificate indicating that we have complied with all covenants contained in the Indenture or whether any default or Event of Default has occurred during the previous year.

If an Event of Default occurs and is continuing and is known to the Trustee, the Trustee must mail to each holder a notice of the Event of Default by the later of 90 days after the Event of Default occurs or 30 days after the Trustee knows of the Event of Default. Except in the case of a default in the payment of principal, premium, if any, or interest with respect to any debt securities, the Trustee may withhold such notice, but only if and so long as the board of directors, the executive committee or a committee of directors or responsible officers of the Trustee in good faith determines that withholding such notice is in the interests of the holders.

Amendments and Waivers

The issuer may amend the Indenture without the consent of any holder of debt securities to:

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In addition, the issuer may amend the Indenture if the holders of a majority in principal amount of all debt securities of each series that would be affected then outstanding under the Indenture consent to it. The issuer may not, however, without the consent of each holder of outstanding debt securities of each series that would be affected, amend the Indenture to:

The consent of the holders is not necessary under the Indenture to approve the particular form of any proposed amendment. It is sufficient if such consent approves the substance of the proposed amendment. After an amendment under the Indenture requiring the consent of the holders of any series of debt securities becomes effective, the issuer is required to mail to all holders a notice briefly describing the amendment with respect to other holders. The failure to give, or any defect in, such notice to any holder, however, will not impair or affect the validity of the amendment with respect to other holders.

The holders of a majority in aggregate principal amount of the outstanding debt securities of each affected series, on behalf of all such holders, and subject to certain rights of the Trustee, may waive:

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except that such majority of holders may not waive a default:

Satisfaction and Discharge

The issuer may discharge all its obligations under the Indenture with respect to any series of debt securities, other than its obligation to register the transfer and exchange of debt securities of such series, provided that either:

and, in either case, the issuer has paid all other sums payable under the Indenture.

Defeasance

At any time, the issuer may terminate, with respect to debt securities of a particular series, all its obligations under such series of debt securities and the Indenture, which we call a “legal defeasance.” If the issuer decides to make a legal defeasance, however, the issuer may not, among other things, terminate its obligations:

If the issuer exercises its legal defeasance option, any guarantee will terminate with respect to that series of debt securities.

At any time the issuer may also effect a “covenant defeasance,” which means it has elected to terminate its obligations with respect to debt securities of a particular series under the covenants applicable to such series of debt securities and described in the prospectus supplement applicable to such series, other than as described in such prospectus supplement.

The legal defeasance option may be exercised notwithstanding a prior exercise of the covenant defeasance option. If the legal defeasance option is exercised, payment of the affected series of debt securities may not be accelerated because of an Event of Default with respect to that series. If the covenant defeasance option is exercised, payment of the affected series of debt securities may not be accelerated because of an Event of Default specified in the fourth and sixth (and with respect to any guarantor, the fifth) bullet points in the first paragraph under “—Events of Default, Remedies and Notice—Events of Default” or an Event of Default that is added specifically for such series and described in the prospectus supplement applicable to such series.

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In order to exercise either defeasance option, the issuer must:

Subordination

Debt securities of a series may be subordinated to our “Senior Indebtedness,” which we define generally to include any obligation created or assumed by us (or, if the series is guaranteed, the guarantor) for the repayment of borrowed money and any guarantee therefor, whether outstanding or hereafter issued, unless, by the terms of the instrument creating or evidencing such obligation, it is provided that such obligation is subordinate or not superior in right of payment to such debt securities (or, if the series is guaranteed, the guarantee of the guarantor), or to other obligations which are pari passu with or subordinated to such debt securities (or, if the series is guaranteed, the guarantee of the guarantor). Subordinated debt securities will be subordinate in right of payment, to the extent and in the manner set forth in the Indenture and the prospectus supplement relating to such series, to the prior payment of all of our indebtedness and that of the guarantor, if applicable, that is designated as “Senior Indebtedness” with respect to such series.

The holders of our Senior Indebtedness or, if applicable, of the Senior Indebtedness of a guarantor, will receive payment in full of the Senior Indebtedness before holders of subordinated debt securities will receive any payment of principal, premium, if any, or interest with respect to the subordinated debt securities:

Until the Senior Indebtedness is paid in full, any distribution to which holders of subordinated debt securities would otherwise be entitled will be made to the holders of Senior Indebtedness, except that the holders of subordinated debt securities may receive units representing limited partner interests in us and any debt securities that are subordinated to Senior Indebtedness to at least the same extent as the subordinated debt securities.

If the issuer does not pay any principal, premium, if any, or interest with respect to Senior Indebtedness within any applicable grace period (including at maturity), or any other default on Senior Indebtedness occurs and the maturity of the Senior Indebtedness is accelerated in accordance with its terms, the issuer and any guarantor may not:

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Generally, “Designated Senior Indebtedness” will include:

During the continuance of any default, other than a default described in the paragraph prior to the immediately preceding paragraph, that may cause the maturity of any Designated Senior Indebtedness to be accelerated immediately without further notice, other than any notice required to effect such acceleration, or the expiration of any applicable grace periods, the issuer may not make any payments on the subordinated debt securities or any related guarantee for a period called the “Payment Blockage Period.” A Payment Blockage Period will commence on the receipt by the issuer and the Trustee of written notice of the default, called a “Blockage Notice,” from the representative of any Designated Senior Indebtedness specifying an election to effect a Payment Blockage Period and will end 179 days thereafter.

The Payment Blockage Period may be terminated before its expiration:

Unless the holders of the Designated Senior Indebtedness have accelerated the maturity of the Designated Senior Indebtedness, the issuer may resume payments on the subordinated debt securities after the expiration of the Payment Blockage Period.

Generally, not more than one Blockage Notice may be given in any period of 360 consecutive days. The total number of days during which any one or more Payment Blockage Periods are in effect, however, may not exceed an aggregate of 179 days during any period of 360 consecutive days.

After all Senior Indebtedness is paid in full and until the subordinated debt securities are paid in full, holders of the subordinated debt securities shall be subrogated to the rights of holders of Senior Indebtedness to receive distributions applicable to Senior Indebtedness.

As a result of the subordination provisions described above, in the event of insolvency, the holders of Senior Indebtedness, as well as certain of the issuer’s general creditors, may recover more, ratably, than the holders of the subordinated debt securities.

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No Personal Liability of General Partner

Our general partner and its directors, officers, employees, incorporators and equity owners, as such, will not be liable for:

By accepting a debt security, each holder will be deemed to have waived and released all such liability. This waiver and release are part of the consideration for our issuance of the debt securities. This waiver may not be effective, however, to waive liabilities under the federal securities laws and it is the view of the SEC that such a waiver is against public policy.

Book Entry, Delivery and Form

A series of debt securities may be issued in the form of one or more global certificates deposited with a depositary. We expect that The Depository Trust Company, New York, New York, or “DTC,” will act as depositary. If a series of debt securities is issued in book-entry form, one or more global certificates will be issued and deposited with or on behalf of DTC and physical certificates will not be issued to each holder. A global security may not be transferred unless it is exchanged in whole or in part for a certificated security, except that DTC, its nominees and their successors may transfer a global security as a whole to one another.

DTC will keep a computerized record of its participants, such as a broker, whose clients have purchased the debt securities. The participants will then keep records of their clients who purchased the debt securities. Beneficial interests in global securities will be shown on, and transfers of beneficial interests in global securities will be made only through, records maintained by DTC and its participants.

DTC advises us that it is:

DTC is owned by a number of its participants and by the New York Stock Exchange, Inc., The American Stock Exchange, Inc. and the Financial Industry Regulatory Authority. The rules that apply to DTC and its participants are on file with the SEC.

DTC holds securities that its participants deposit with DTC. DTC also records the settlement among participants of securities transactions, such as transfers and pledges, in deposited securities through computerized records for participants’ accounts. This eliminates the need to exchange certificates. Participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations.

Principal, premium, if any, and interest payments due on the global securities will be wired to DTC’s nominee. The issuer, any guarantor, the Trustee and any paying agent will treat DTC’s nominee as the owner of the global securities for all purposes. Accordingly, the issuer, the trustee and any paying agent will have no direct responsibility or liability to pay amounts due on the global securities to owners of beneficial interests in the global securities.

It is DTC’s current practice, upon receipt of any payment of principal, premium, if any, or interest, to credit participants’ accounts on the payment date according to their respective holdings of beneficial interests in the

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global securities as shown on DTC’s records. In addition, it is DTC’s current practice to assign any consenting or voting rights to participants, whose accounts are credited with debt securities on a record date, by using an omnibus proxy.

Payments by participants to owners of beneficial interests in the global securities, as well as voting by participants, will be governed by the customary practices between the participants and the owners of beneficial interests, as is the case with debt securities held for the account of customers registered in “street name.” Payments to holders of beneficial interests are the responsibility of the participants and not of DTC, the Trustee, any guarantor or us.

Beneficial interests in global securities will be exchangeable for certificated securities with the same terms in authorized denominations only if:

The Trustee

A separate trustee may be appointed for any series of debt securities. We use the term “Trustee” to refer to the trustee appointed with respect to any such series of debt securities. We may maintain banking and other commercial relationships with the Trustee and its affiliates in the ordinary course of business, and the Trustee may own debt securities.

Governing Law

The Indenture and the debt securities will be governed by, and construed in accordance with, the laws of the State of New York.

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DESCRIPTION OF THE WARRANTS

General Description of Warrants

Boardwalk Pipelines, LP may issue warrants for the purchase of debt securities. Warrants may be issued independently or together with other securities and may be attached to or separate from any offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between Boardwalk Pipelines, LP and a bank or trust company, as warrant agent. The warrant agent will act solely as our agent in connection with the warrants and will not have any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants. A copy of the warrant agreement will be filed with the SEC in connection with any offering of warrants. The prospectus supplement relating to a particular issue of warrants will describe the terms of the warrants, including, among other things, the following:

Exercise of Warrants

Each warrant will entitle the holder of the warrant to purchase at the exercise price set forth in the applicable prospectus supplement the principal amount of securities being offered. Holders may exercise warrants at any time up to the close of business on the expiration date or on specified dates set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants are void unless the expiration date is otherwise extended in accordance with the terms of the applicable warrants. Holders may exercise warrants as set forth in the prospectus supplement relating to the warrants being offered. Until you exercise your warrants to purchase securities, you will not have any rights as a holder of such securities, as the case may be, by virtue of your ownership of warrants.

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DESCRIPTION OF THE RIGHTS

We and Boardwalk Pipelines, LP may issue rights to purchase warrants or debt securities, as applicable. These rights may be issued independently or together with any other security offered hereby and may or may not be transferable by the person purchasing or receiving the rights in such offering. In connection with any offering of such rights, we may enter into a standby arrangement with one or more underwriters or other purchasers pursuant to which the underwriters or other purchasers may be required to purchase any securities remaining unsubscribed for after such offering.

We or Boardwalk Pipelines, LP, as applicable, will enter into a rights agent agreement with a bank or trust company, as rights agent. The rights agent will act solely as our agent in connection with the certificates relating to the rights and will not assume any obligation or relationship of agency or trust with any holders of rights certificates or beneficial owners of rights. A copy of the rights certificates relating to each series of rights will be filed with the SEC. The prospectus supplement relating to a particular offering of rights will describe the terms of the rights, including, among other things, the following:

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PLAN OF DISTRIBUTION

Under this prospectus, we intend to offer our securities to the public through one or more broker-dealers, underwriters or directly to investors.

We will fix a price or prices of our securities at:

We may change the price of the securities offered from time to time.

We will pay or allow distributors’ or sellers’ commissions that will not exceed those customary in the types of transactions involved. Broker-dealers may act as agent or may purchase securities as principal and thereafter resell the securities from time to time:

Broker-dealers or underwriters may receive compensation in the form of underwriting discounts or commissions and may receive commissions from purchasers of the securities for whom they may act as agents. If any broker-dealer purchases the securities as principal, it may effect resales of the securities from time to time to or through other broker-dealers, and other broker-dealers may receive compensation in the form of concessions or commissions from the purchasers of securities for whom they may act as agents.

To the extent required, the names of the specific managing underwriter or underwriters, if any, as well as other important information, will be set forth in prospectus supplements. In that event, the discounts and commissions we will allow or pay to the underwriters, if any, and the discounts and commissions the underwriters may allow or pay to dealers or agents, if any, will be set forth in, or may be calculated from, the prospectus supplements. Any underwriters, brokers, dealers and agents who participate in any sale of the securities may also engage in transactions with, or perform services for, us or our affiliates in the ordinary course of their businesses. We may indemnify underwriters, brokers, dealers and agents against specific liabilities, including liabilities under the Securities Act.

Offers to purchase securities may be solicited directly by us and the sale thereof may be made by us directly to institutional investors or others, who may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale thereof. The terms of any such sales will be described in the prospectus supplement relating thereto.

To the extent required, this prospectus may be amended or supplemented from time to time to describe a specific plan of distribution. The place and time of delivery for the securities in respect of which this prospectus is delivered will be set forth in the accompanying prospectus supplement.

In connection with offerings under this shelf registration and in compliance with applicable law, underwriters, brokers or dealers may engage in transactions which stabilize or maintain the market price of the securities at levels above those which might otherwise prevail in the open market. Specifically, underwriters, brokers or dealers may over-allot in connection with offerings, creating a short position in the securities for their own accounts. For the purpose of covering a syndicate short position or stabilizing the price of the securities, the underwriters, brokers or dealers may place bids for the securities or effect purchases of the securities in the open

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market. Finally, the underwriters may impose a penalty whereby selling concessions allowed to syndicate members or other brokers or dealers for distribution the securities in offerings may be reclaimed by the syndicate if the syndicate repurchases previously distributed securities in transactions to cover short positions, in stabilization transactions or otherwise. These activities may stabilize, maintain or otherwise affect the market price of the securities, which may be higher than the price that might otherwise prevail in the open market, and, if commenced, may be discontinued at any time.

LEGAL MATTERS

Certain legal matters in connection with the securities will be passed upon by Vinson & Elkins L.L.P., Houston, Texas, as our counsel. Any underwriters will be advised about other issues relating to any offering by their own legal counsel.

EXPERTS

The consolidated financial statements incorporated in this prospectus by reference from the Boardwalk Pipeline Partners, LP Annual Report on Form 10-K for the year ended December 31, 2017 and the effectiveness of Boardwalk Pipeline Partners, LP internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

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PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

The following table sets forth all expenses payable by Boardwalk Pipeline Partners, LP and Boardwalk Pipelines, LP (other than underwriting discounts and commissions) in connection with the issuance and distribution of the securities.

Subject to any terms, conditions or restrictions set forth in our partnership agreement, Section 17-108 of the Delaware Revised Uniform Limited Partnership Act empowers a Delaware limited partnership to indemnify and hold harmless any partner or other person from and against all claims and demands whatsoever.

Under our partnership agreement, we will indemnify the following persons in most circumstances, to the fullest extent permitted by law, from and against all losses, claims, damages, or similar events:

Any indemnification under these provisions will only be out of our assets. Unless it otherwise agrees, our general partner will not be personally liable for, or have any obligation to contribute or loan funds or assets to us to enable us to effectuate, indemnification. Our partnership agreement permits us to purchase insurance against liabilities asserted against and expenses incurred by persons for our activities, regardless of whether we would have the power to indemnify the person against liabilities under our partnership agreement.

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(a) The following documents are filed as exhibits to this registration statement, including those exhibits incorporated herein by reference to a prior filing under the Securities Act or the Exchange Act as indicated below.

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(b) Financial Statement Schedules

Not Applicable.

(a) Each of the undersigned registrants hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (i), (ii) and (iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the registrants pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrants pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which the prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made

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in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date; or

(5) That, for the purpose of determining liability of the registrants under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, each of the undersigned registrants undertakes that in a primary offering of securities of the undersigned registrants pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrants will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrants relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrants or used or referred to by the undersigned registrants;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrants or its securities provided by or on behalf of an undersigned registrants; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

Each of the undersigned registrants hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrants’ annual report pursuant to section 13(a) or section 15(d) of the Securities Exchange Act of 1934 that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

Each of the undersigned registrants hereby undertakes to supplement the prospectus, after the expiration of the subscription period, if any securities not taken by existing securityholders are to be offered to the public, to set forth the results of the subscription offer, the transactions by the underwriters during the subscription period, the amount of unsubscribed securities to be purchased by the underwriters, and the terms of any subsequent reoffering thereof. If any public offering by the underwriters is to be made on terms differing from those set forth on the cover page of the prospectus, a post-effective amendment will be filed to set forth the terms of such offering.

Each of the undersigned registrants hereby undertakes to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of Regulation S-X are not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of any registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or

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proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.

Each of the undersigned registrants hereby undertakes that:

(1) For purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this registration statement as of the time it was declared effective.

(2) For the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

Each undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act (“Act”) in accordance with the rules and regulations prescribed by the Commission under Section 305(b)2 of the Act.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, each of the registrants certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Houston, State of Texas on December 7, 2018.

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POWER OF ATTORNEY

Each person whose signature appears below hereby constitutes and appoints Stanley C. Horton, Jamie L. Buskill and Michael E. McMahon, and each of them, any of whom may act without the joinder of the other, as his lawful attorneys-in-fact and agents, with full power of substitution and resubstitution for him or her in any and all capacities, to sign any or all amendments or post-effective amendments to this registration statement, or any registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended, and to file the same, with exhibits hereto and other documents in connection therewith or in connection with the registration of the securities under the Securities Act of 1933, as amended, with the Securities and Exchange Commission, granting unto such attorneys-in-fact and agents full power and authority to do and perform each and every act and thing requisite and necessary in connection with such matters and hereby ratifying and confirming all that such attorneys-in-fact and agents or his substitutes may do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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