San Diego 100

The San Diego 100 is a challenging 100-mile mountain endurance race scheduled for Friday, May 1, 2026, at Lake Cuyamaca, California. This technical loop course traverses four distinct recreational areas, including sections of the Pacific Crest Trail (PCT) and Noble Canyon, featuring approximately 15,400 feet of total vertical gain. Recognized as a qualifier for the Western States 100, the race is notorious for its difficult technical terrain combined with the hot, dry conditions characteristic of the San Diego County mountains.

The course is geographically diverse, crossing through Cuyamaca and Anza Borrego State Parks as well as the Mt. Laguna Recreational Area. Runners move from high-altitude ridge lines to arid desert-transition zones. In early May, the climate in the Laguna Mountains can be extreme, with daytime temperatures often exceeding 27°C (80°F) while nighttime temperatures on the PCT sections can drop toward 4°C (40°F). The technical nature of the Noble Canyon trails, characterized by rock gardens and steep switchbacks, contributes to the race's reputation for being significantly harder than its elevation profile suggests.

Logistically, registration for the 2026 event opens on January 1 and requires a qualifying finish: a 50-mile race under 13 hours or any 100K/100M finish within the designated two-year window. A mandatory 6-hour volunteer service requirement or a $100 donation to "Trailfit" is strictly enforced for all participants. The race features a dedicated Solo Division for those running without pacers or crews, offering a $10 discount and a unique belt buckle. Additional incentives include a 10% discount for active military and first responders, and the Scotty Mills Scholarships, which provide free entry to community-focused runners. Top historical times for the event include Karl Meltzer’s 2006 record of 15:48:00 and Makai Clemons' 2023 finish of 16:27:02.