UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 1, 2013 (October 31, 2013)

SPECTRA ENERGY PARTNERS, LP

(Exact name of registrant as specified in its charter)

5400 Westheimer Court

Houston, Texas 77056

(Address of principal executive offices)

(713) 627-5400

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Amendment to Contribution Agreement

As previously disclosed, on August 5, 2013, Spectra Energy Partners, LP (the “Partnership”) entered into a Contribution Agreement (the “Contribution Agreement”) with Spectra Energy Corp (“SE Corp”), pursuant to which SE Corp agreed to contribute to the Partnership substantially all of its interests in its subsidiaries (the “Contributed Entities”) that own U.S. transmission and storage and liquids assets and to assign to the Partnership its interests in certain related contracts (the “Dropdown Transactions”).

On October 31, 2013, the Partnership and SE Corp entered into the First Amendment to Contribution Agreement (the “Amendment”). Among other things, the Amendment (1) provides for the refinancing of certain intercompany indebtedness rather than the assignment of such indebtedness to the Partnership and (2) revises provisions relating to the treatment of performance and surety bonds, certain working capital adjustments and third party indebtedness.

The foregoing description of the Amendment is not complete and is qualified in its entirety by reference to the full and complete terms of the Amendment, which is attached to this Current Report on Form 8-K as Exhibit 2.1.

Amended and Restated Omnibus Agreement

In connection with the transactions contemplated by the Contribution Agreement, as amended by the Amendment (the “Amended Contribution Agreement”), on November 1, 2013, the Partnership entered into an Amended and Restated Omnibus Agreement with SE Corp, Spectra Energy Partners (DE) GP, LP, the general partner of the Partnership (the “General Partner”), and Spectra Energy Partners GP, LLC, the general partner of the General Partner (“GP LLC”). The Amended and Restated Omnibus Agreement eliminates the limitation on the amount that SE Corp is entitled to as reimbursement from the Partnership for corporate services and limits the scope of SE Corp’s obligation to indemnify the Partnership for certain liabilities.

The foregoing description of the Amended and Restated Omnibus Agreement is not complete and is qualified in its entirety by reference to the full and complete terms of the Amended and Restated Omnibus Agreement, which is attached to this Current Report on Form 8-K as Exhibit 10.1.

Credit Agreement

On November 1, 2013, the Partnership amended and restated its existing revolving credit agreement by entering into an amended and restated $2 billion revolving credit agreement (the “Credit Agreement”) with the initial lenders and issuing banks named in the Credit Agreement and Citibank, N.A., as Administrative Agent. JPMorgan Chase Bank, N.A. and The Royal Bank of Scotland plc acted as Syndication Agents, Bank of America, N.A. and Wells Fargo Bank, National Association acted as Documentation Agents, and J.P. Morgan Securities LLC, Citigroup Global Markets Inc., RBS Securities Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, and Wells Fargo Securities, LLC acted as Joint Lead Arrangers and Joint Bookrunners.

The Credit Agreement contains a sublimit of $250 million for issuances of letters of credit, $150 million of which may be denominated in alternative currencies. Interest rates on borrowings under the Credit Agreement will be based on prevailing interest rates as described in the Credit Agreement and the credit ratings of the Partnership. Outstanding borrowings under the Credit Agreement mature on November 1, 2018, which may be extended for up to two additional one-year periods at the request of the Partnership (subject to the agreement of the applicable class of lenders having commitments representing more than 50% of the aggregate commitments of all lenders in the applicable class under the Credit Agreement). The Credit Agreement also provides for additional revolving commitments under the Credit Agreement, which may consist of incremental term loans that, at the Partnership’s election, automatically increase the aggregate amount of the revolving commitments upon any prepayment thereof, provided that the aggregate amount of revolving commitments under the Credit Agreement, including such additional revolving commitments and the aggregate principal amount outstanding under any incremental term loans

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that by their terms automatically increase the aggregate amount of the revolving commitments upon any prepayment thereof, does not exceed $3 billion. The Partnership is permitted to request an unlimited amount of incremental term loans under the Credit Agreement provided that such loans are fully cash collateralized and, to the extent such term loans automatically increase the aggregate amount of revolving commitments upon any prepayment thereof, the aggregate amount of such term loans plus the aggregate amount of any increases in revolving commitments does not exceed $1 billion.

The Credit Agreement contains customary representations, warranties and covenants, including limitations on the creation of liens on the Partnership’s and certain of its subsidiaries’ assets, limitations on consolidations, mergers and the sale of all or substantially all of the assets of the Partnership and certain of its subsidiaries, and limitations on certain transactions with affiliates. The Partnership has agreed to maintain a consolidated leverage ratio, as defined in the Credit Agreement, of less than or equal to 5.00 to 1.0, measured at the end of each fiscal quarter of the Partnership, provided that for three fiscal quarters subsequent to certain acquisitions, the Partnership’s consolidated leverage ratio may be up to 5.50 to 1.0. Upon the occurrence of certain events of default, the Partnership’s obligations under the Credit Agreement may be accelerated. Such events of default include payment defaults to lenders under the Credit Agreement, covenant defaults and other customary defaults.

The Credit Agreement provides that proceeds from borrowings under the Credit Agreement may be used for the Partnership’s and its subsidiaries’ general corporate purposes, including liquidity support for outstanding commercial paper and acquisitions.

Certain of the lenders under the Credit Agreement and their respective affiliates perform various financial advisory, investment banking and commercial banking services from time to time for the Partnership and its affiliates, for which they received or will receive customary fees and expense reimbursement.

The foregoing description of the Credit Agreement is not complete and is qualified in its entirety by reference to the full and complete terms of the Credit Agreement, which is attached to this Current Report on Form 8-K as Exhibit 10.2.

Term Loan Agreement

On November 1, 2013, the Partnership entered into a $400 million senior unsecured term loan credit agreement (the “Term Loan Agreement”) with the initial lenders named in the Term Loan Agreement and The Bank of Tokyo-Mitsubishi UFJ, LTD., as Administrative Agent. Bank of America, N.A. acted as Syndication Agent and Merrill Lynch, Pierce, Fenner & Smith Incorporated and The Bank of Tokyo Mitsubishi UFJ, LTD. acted as Joint Lead Arrangers and Joint Bookrunners.

Interest rates on borrowings under the Term Loan Agreement will be based on prevailing interest rates as described in the Term Loan Agreement and the credit ratings of the Partnership. Outstanding borrowings under the Term Loan Agreement mature on November 1, 2018.

The Term Loan Agreement contains customary representations, warranties and covenants, including limitations on the creation of liens on the assets of the Partnership and certain of its subsidiaries, limitations on consolidations, mergers and the sale of all or substantially all of the assets of the Partnership and certain of its subsidiaries and limitations on certain transactions with affiliates. The Partnership has agreed to maintain a consolidated leverage ratio, as defined in the Term Loan Agreement, of less than or equal to 5.00 to 1.0, measured at the end of each fiscal quarter, provided that for three fiscal quarters subsequent to certain acquisitions, the Partnership’s consolidated leverage ratio may be up to 5.50 to 1.0. Upon the occurrence of certain events of default, the Partnership’s obligations under the Term Loan Agreement may be accelerated. Such events of default include payment defaults to lenders under the Term Loan Agreement, covenant defaults and other customary defaults.

The Term Loan Agreement provides that proceeds from borrowings under the Term Loan Agreement may be used for the Partnership’s and its subsidiaries’ general corporate purposes, including acquisitions.

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Certain of the lenders under the Term Loan Agreement and their respective affiliates perform various financial advisory, investment banking and commercial banking services from time to time for the Partnership and its affiliates, for which they received or will receive customary fees and expense reimbursement.

The foregoing description of the Term Loan Agreement is not complete and is qualified in its entirety by reference to the full and complete terms of the Term Loan Agreement, which is attached to this Current Report on Form 8-K as Exhibit 10.3.

The information set forth under Item 1.01 is incorporated herein by reference. Pursuant to the Amended Contribution Agreement, on November 1, 2013, the Partnership and SE Corp completed the closing of substantially all of the Dropdown Transactions (the “First Closing”). The remaining closings of the Dropdown Transactions are expected to occur at least 12 months following the First Closing (the “Second Closing”) and at least 12 months following the Second Closing (the “Third Closing”).

In connection with the First Closing, the Partnership paid to SE Corp aggregate consideration consisting of (i) 167,639,491 newly issued common units and 3,421,214 newly issued general partner units issued to certain subsidiaries of SE Corp and to the General Partner, respectively, (ii) approximately $70.4 million in cash representing a loan from the Partnership to one of the Contributed Entities, the proceeds of which were used to repay intercompany indebtedness to a subsidiary of SE Corp, (iii) approximately $2.2 billion in cash paid to the General Partner and another subsidiary of SE Corp, after taking into account customary closing adjustments, and (iv) the assumption (indirectly by acquisition of the Contributed Entities) of approximately $2.4 billion of third-party indebtedness of the Contributed Entities. The cash consideration was funded with the net proceeds from the Partnership’s issuance and sale on September 25, 2013 of its 2.950% Senior Notes due 2018, 4.750% Senior Notes due 2024 and 5.950% Senior Notes due 2043, other restricted funds held by the Partnership and through borrowings under the Term Loan Agreement. After the Second Closing, SE Corp will have received a total of approximately 172 million newly issued common units and 3.5 million newly issued general partner units.

A description of the assets acquired in connection with the First Closing is presented in Item 8.01.

The information set forth under Item 1.01 regarding the entry into the Credit Agreement and the Term Loan Agreement above is hereby incorporated into this Item 2.03 by reference.

The information set forth under Item 2.01 above with respect to the Partnership’s common units issued to certain subsidiaries of SE Corp and to the General Partner is incorporated herein by reference. This private placement of Partnership common units issued pursuant to the Amended Contribution Agreement was made in reliance upon an exemption from the registration requirements of the Securities Act of 1933, as amended, pursuant to Section 4(a)(2).

On November 1, 2013, Ms. Julie A. Dill resigned as President and Chief Executive Officer of GP LLC. Ms. Dill will continue to serve as a director of GP LLC and as group vice president of strategy for SE Corp.

On November 1, 2013, Mr. Gregory L. Ebel was appointed Chairman of the Board, President and Chief Executive Officer of GP LLC. Mr. Ebel, age 49, is also President, Chief Executive Officer and Director of SE Corp. Mr. Ebel served as Group Executive and Chief Financial Officer of SE Corp from January 2007 until assuming his

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current position at SE Corp on January 1, 2009. Prior to that time, Mr. Ebel served as President of Union Gas Limited from January 2005 until January 2007, and Vice President, Investor & Shareholder Relations of Duke Energy Corporation from November 2002 until January 2005. Mr. Ebel joined Duke Energy in March 2002 as Managing Director of Mergers and Acquisitions in connection with Duke Energy’s acquisition of Westcoast Energy Inc. Mr. Ebel is also a director of The Mosaic Company and a member of its Audit Committee.

On November 1, 2013, Mr. Fred J. Fowler resigned as Chairman of the Board of GP LLC. Mr. Fowler will continue to serve as a director of GP LLC.

In connection with the First Closing, on November 1, 2013, the Partnership amended and restated its First Amended and Restated Agreement of Limited Partnership to, among other things, (1) clarify what types of unitholders constitute “Eligible Unitholders” and (2) change the distribution date with respect to each fiscal quarter to the date that is 60 days following the close of such quarter. The foregoing description is not complete and is qualified in its entirety by reference to the full and complete terms of the Second Amended and Restated Agreement of Limited Partnership, a copy of which is attached to this Current Report on Form 8-K as Exhibit 3.1.

In connection with the First Closing, on November 1, 2013, GP LLC amended and restated its Second Amended and Restated Limited Liability Company Agreement to, among other things, (1) reflect that Spectra Energy Southeast Pipeline Corporation is now the sole member of GP LLC and (2) change the distribution date with respect to each fiscal quarter to the date that is 60 days following the close of such quarter. The foregoing description is not complete and is qualified in its entirety by reference to the full and complete terms of the Third Amended and Restated Limited Liability Company Agreement, a copy of which is attached to this Current Report on Form 8-K as Exhibit 3.2.

On November 1, 2013, the Partnership and SE Corp issued a joint press release announcing the consummation of the First Closing. A copy of the press release is attached to this Current Report on Form 8-K as Exhibit 99.1. The information in Exhibit 99.1 is being furnished pursuant to this Item 7.01.

Description of Dropdown Assets

The assets owned by the Contributed Entities, as well as the assets included in the 40% ownership interest in the U.S. portion (Express US) and 100% ownership interest in the Canadian portion (Express Canada) of the Express-Platte crude oil pipeline system (collectively, the Express-Platte System) that we acquired from SE Corp on August 2, 2013, include natural gas, crude oil and natural gas liquids (NGL) pipelines and storage facilities that provide transportation and storage services for local distribution companies, electric power generators, exploration and production companies, and industrial and commercial customers, as well as energy marketers. Transportation and storage services are generally provided under firm agreements where customers reserve capacity in pipelines and storage facilities. The vast majority of these agreements provide for fixed reservation charges that are paid monthly regardless of actual volumes transported on the pipelines or injected or withdrawn from the storage facilities, plus a small variable component that is based on volumes transported, injected or withdrawn, which is intended to recover variable costs.

The Contributed Entities, with respect to their natural gas assets, also offer interruptible transportation and storage services where customers can use capacity if it is available at the time of the request. Interruptible revenues depend on the amount of volumes transported or stored and the associated market rates for this interruptible service, subject to a cost-based regulated rate cap. New projects placed into natural gas service may initially have higher levels of interruptible services at inception. The operations at the storage facilities also provide a variety of other value-added services including natural gas parking, loaning and balancing services to meet the needs of customers. In addition, the Contributed Entities, with respect to their crude oil and NGL assets, offer service to customers on capacity made available to any customer that has not previously executed a contract reserving capacity in the crude oil or NGL facility. Revenues from such non-contract customers depend on the amount of volumes transported or stored and the associated rate for such service.

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Most of the Contributed Entities’ pipeline and storage operations are regulated by the Federal Energy Regulatory Commission (FERC) and are subject to the jurisdiction of various federal, state and local environmental agencies. FERC is the U.S. agency that regulates the transportation of natural gas, crude oil and NGLs in interstate commerce. Our Canadian pipeline and storage operations are regulated by Canada’s National Energy Board.

The Contributed Entities and their pipeline systems included in the Dropdown Transactions include:

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The natural gas and crude oil storage businesses included in the Dropdown Transactions include:

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There can be no assurance that the Second Closing and the Third Closing will be completed in the anticipated time frame, or at all, or that anticipated benefits of the Dropdown Transactions will be realized.

The financial statements required by this Item 9.01 are not included in this Current Report on Form 8-K. These financial statements will be filed within 71 calendar days after the date on which this Current Report on Form 8-K is required to be filed.

(d) Exhibits.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: November 1, 2013

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EXHIBIT INDEX

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