EXHIBIT 5.1


Writer's Phone: 713-758-2222                            E-mail:  velaw@velaw.com
Writer's Fax: 713-758-2346                                  Web:   www.velaw.com

                                 October 19, 2001

Sunoco Logistics Partners L.P.
1801 Market Street
Philadelphia, Pennsylvania  19103

Gentlemen:

     We have acted as counsel to Sunoco Logistics Partners L.P., a Delaware
limited partnership (the "Partnership"), and Sunoco Partners LLC, a Delaware
limited liability company and the general partner of the Partnership (the
"General Partner"), in connection with the registration under the Securities Act
of 1933, as amended (the "Securities Act") of the offering and sale of up to an
aggregate of 5,000,000 common units representing limited partner interests in
the Partnership (the "Common Units").

     As the basis for the opinion hereinafter expressed, we examined such
statutes, including the Delaware Uniform Revised Limited Partnership Act,
corporate records and documents, certificates of corporate and public officials,
and other instruments and documents as we deemed necessary or advisable for the
purposes of this opinion. In such examination, we assumed the authenticity of
all documents submitted to us as originals and the conformity with the original
documents of all documents submitted to us as copies.

     Based on the foregoing and on such legal considerations as we deem
relevant, we are of the opinion that:

     1.   The Partnership has been duly formed and is validly existing as a
          limited partnership under the Delaware Revised Uniform Limited
          Partnership Act.

     2.   The Common Units, when issued and paid for under the Partnership's
          Registration Statement on Form S-1 (the "Registration Statement")
          relating to the Common Units, will be duly authorized, validly issued,
          fully paid and nonassessable, except as such nonassessability may be
          affected by the matters below:

          .    If a court were to determine that the right or exercise of the
               right under the Agreement of Limited Partnership of the
               Partnership (the "Partnership Agreement") by the holders of
               Common Units and subordinated units (the




Sunoco Logistics Partners L.P.
October 19, 2001
Page 2




               "Limited Partners") of the Partnership as a group

               .    to remove or replace the General Partner;

               .    to approve certain amendments to the Partnership Agreement;
                    or

               .    to take certain other actions under the Partnership
                    Agreement that constitute "participation in the control" of
                    the Partnership's business for the purposes of the Delaware
                    Act,

          then the Limited Partners could be held personally liable for the
          Partnership's obligations under the laws of Delaware, to the same
          extent as the General Partner with respect to persons who transact
          business with the Partnership reasonably believing, based on the
          conduct of any of the Limited Partners, that such Limited Partner is a
          general partner.

          .    Section 17-607 of the Delaware Act provides that a limited
               partner who receives a distribution and knew at the time of the
               distribution that it was made in violation of the Delaware Act
               shall be liable to the limited partnership for three years for
               the amount of the distribution.

     We hereby consent to the statements with respect to us under the heading
"Legal Matters" in the prospectus forming a part of the Registration Statement
and to the filing of this opinion as an exhibit to the Registration Statement,
but we do not thereby admit that we are within the class of persons whose
consent is required under the provisions of the Securities Act of 1933, as
amended, or the rules and regulations of the Securities and Exchange Commission
issued thereunder.

                                            Very truly yours,

                                            /s/ Vinson & Elkins L.L.P.
                                            ----------------------------
                                            VINSON & ELKINS L.L.P.