May 14, 2015

VIA EDGAR

Securities and Exchange Commission

Division of Corporation Finance

100 F. Street, N.E.

Washington, D.C. 20549

Attention: John Dana Brown

Sonia Bednarowski

Beverly Singleton

Lyn Shenk

Re: Planet Fitness, Inc.

Draft Registration Statement on Form S-1, confidentially submitted March 25, 2015

CIK No. 0001637207

Ladies and Gentlemen:

On behalf of Planet Fitness, Inc. (the “Company”), in response to Comment 1 contained in the letter dated April 21, 2015 from the staff (the “Staff”) of the Securities and Exchange Commission in connection with the above-referenced Draft Registration Statement (the “Registration Statement”), as discussed with the Staff, we submit via EDGAR for review the supplemental pages to the Registration Statement attached as Annex A, which include pictures and graphics to be included in the Registration Statement. For your convenience, the Company is also providing to the Staff a printed copy of the supplemental pages attached as Annex A.

Securities and Exchange Commission - 2 - May 14, 2015

If you have any questions or comments about this letter or need any further information, please call the undersigned at (617) 951-7473 or Thomas J. Fraser of our offices at (617) 951-7063.

Very truly yours,

/s/ David A. Fine

David A. Fine

cc: Chris Rondeau (Planet Fitness, Inc.)

Dorvin Lively (Planet Fitness, Inc.)

D. Rhett Brandon (Simpson Thacher & Bartlett LLP)

John C. Ericson (Simpson Thacher & Bartlett LLP)

Securities and Exchange Commission - 3 - May 14, 2015

Annex A

[Attached]