WES Western Midstream Partners LP

FREE WRITING PROSPECTUS

Filed Pursuant to Rule 433

Registration No. 333-214446

February 21, 2018

WESTERN GAS PARTNERS, LP

Terms Applicable to the Senior Notes due 2028

After giving effect to the issuance and sale of the notes and the application of the net proceeds as set forth under “Use of Proceeds,” as of February 20, 2018, we would have been able to incur the full $1.5 billion of indebtedness under our recently amended revolving credit facility.

The Issuer has filed a registration statement (including a prospectus) with the U.S. Securities and Exchange Commission (the “SEC”) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the Issuer has filed with the SEC for more complete information about the Issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC web site at http://www.sec.gov. Alternatively, the Issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling Mizuho Securities USA LLC toll-free at 1-866-271-7403, Credit Suisse Securities (USA) LLC toll-free at 1-800-221-1037, MUFG Securities Americas Inc. toll-free at 1-877-649-6848 or TD Securities (USA) LLC toll-free at 1-855-495-9846.

This Pricing Supplement is qualified in its entirety by reference to the related preliminary prospectus supplement dated February 21, 2018 (the “Preliminary Prospectus Supplement”). The information in this Pricing Supplement supplements the Preliminary Prospectus Supplement and supersedes the information in the Preliminary Prospectus Supplement to the extent inconsistent with the information in the Preliminary Prospectus Supplement.