San Diego 100
Lake Cuyamaca, United States • 1 May 2026
Event Overview
The San Diego 100 is a 100-mile ultramarathon scheduled for May 1-2, 2026. The event features two divisions: a standard 100-mile race and a Solo Division for runners competing without crew or pacer support. Solo runners receive a $10 registration discount. A one-hour early start option is available for runners over the age of 60, though aid stations open at the standard times.
Course Details
The course is a loop consisting of approximately 90% single-track trail. It traverses four recreational areas in the mountains of eastern San Diego County, including sections of the Pacific Crest Trail (PCT), Noble Canyon, Cuyamaca and Anza Borrego State Parks, and the Mt. Laguna Recreation Area. The terrain is described as very challenging and technical, with hot, dry conditions and approximately 15,400 feet of both climbing and descent. The event is a qualifier for the Western States 100.
Location
The start and finish area is the south parking lot of the Lake Cuyamaca Recreation Area, located on Highway 79 about 9 miles southwest of Julian, California.
Registration and Requirements
Registration opens on January 1, 2026, and will close when the event reaches 300 entrants or on April 15, 2026, whichever comes first. A waitlist will be maintained if the race fills. A prerequisite for entry is the completion of a qualifying race. Applicants must have finished a 50-mile race in under 13 hours, a 100K, or a 100-mile race within the time limits of that event, between January 1, 2024, and April 1, 2026. All applicants are also required to complete 6 hours of volunteer service (such as trail maintenance or volunteering at another ultra) between June 1, 2025, and May 1, 2026. Alternatively, a $100 donation to the Trailfit organization is accepted in lieu of service. Failure to meet this requirement will result in disqualification from participation. Visit the organization's website for the most recent information.