Event or Permit Cancellation: If for any reason the event is cancelled due to an act of nature or other Forest Service permit issues, the race director will make every effort to refund all unobligated funds to entrants or rollover entry fees to a rescheduled race date. Entrants need to understand and accept the fact that there are always risks involved in staging an ultra in the wilderness and there can be no guarantees that all entry fees will be refunded if the run is not held as advertised.

To Apply: Visit UltraSignup here and register.

Qualifications: Entrants must show proof of finishing an officially sanctioned 50-mile race within the event time limits and within 13 hours from January 1, 2022, through March 15, 2024. Completing a 100-mile or 100K event during the last 2 years will also serve as a qualification.

As a requisite for participation, entrants must volunteer 6 hours towards trail maintenance or volunteer work at a running/community event. This requirement must be accomplished before June 1 with mail or email notification (to the RD) once the service is completed. We expect the greater San Diego area participants to complete their volunteer service on the San Diego trails we use for the 100-miler. Information about the San Diego Trailfit program and how to sign up for a workday is located at: San Diego Trailfit.

Please reach out to us by e-mail ( to let us know when you have completed your volunteer service requirement.

Entry Fee: Entry to SD 100 is $325 plus the Ultra Signup fee. If an entrant withdraws from the event and notifies the race director before April 15, 2024, they are entitled to a 50% refund. No rollovers or transfers of entries are permitted once an applicant is a confirmed entrant.