June 5, 2018

Via EDGAR Electronic Transmission

Division of Investment Management

U.S. Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C.  20549

Re:Pacific Funds Series Trust

(File Nos. 333-61366 and 811-10385)

Dear Sir or Madam:

On behalf of Pacific Funds Series Trust, transmitted herewith for filing pursuant to Rule 497 under the Securities Act of 1933, as amended (“Rule 497”), is the exhibit in the eXtensible Business Reporting Language (“XBRL”) format that reflects the risk/return summary information included in the prospectus supplement filed pursuant to Rule 497 on May 30, 2018 (accession number 0001104659-18-036461) to the Pacific Funds Class A, Class B, Class C, Class I, Class R, Advisor Class and Investor Class Prospectus and the Pacific Funds Class P Prospectus dated August 1, 2017, as supplemented. The supplements are incorporated by reference into this Rule 497 document.

If you have any questions or comments, please contact the undersigned at (949) 219-3224 or by e-mail at Mark.Karpe@PacificLife.com.

Sincerely,

/s/ Mark Karpe

Mark Karpe

Assistant Vice President and Counsel

cc:Laurene E. MacElwee, Pacific Life Fund Advisors LLC

Robin S. Yonis, Esq., Pacific Life Fund Advisors LLC

Audrey L. Cheng, Esq., Pacific Life Insurance Company

Anthony H. Zacharski, Esq., Dechert LLP

SCHEDULE OF EXHIBITS TO FORM N-1A

Exhibit
Number	Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase