Race Overview
The San Diego 100 Mile Endurance Run stands as Southern California’s premier 100-mile trail ultramarathon, featuring a challenging clockwise loop course through the diverse and stunning terrain of the Laguna and Cuyamaca Mountains. Established in 2006, this legendary race starts and finishes at Lake Cuyamaca, taking runners through over 13,000 feet of elevation gain across 85-90% single-track trails that traverse five distinct ecological areas: Lake Cuyamaca, Rancho Cuyamaca State Park, Anza Borrego State Park boundaries, Noble Canyon Trail System, Mt. Laguna Recreation Area, and sections of the Pacific Crest Trail.
What makes the San Diego 100 Mile Endurance Run unique among California’s 100-mile races is its incredible diversity of terrain and ecosystems within a single course. The 100.3-mile route combines scenic mountain vistas with challenging desert landscapes, technical single-track through oak woodlands and pine forests, and demanding climbs that include the notorious Noble Canyon ascent, Stonewall Peak, Cuyamaca Peak, and the punishing Sweetwater climb. Weather conditions can vary dramatically throughout the race, from cool mountain mornings to intense desert heat, making proper preparation and gear selection critical for success.
The race attracts ultrarunners from around the world seeking to experience Southern California’s most challenging and scenic 100-mile course. With its combination of technical terrain, significant elevation changes, and variable weather conditions, the San Diego 100 provides the ultimate test of mountain and desert ultrarunning skills. The race’s reputation for stunning natural beauty, combined with its demanding course profile, has established it as a premier destination event that showcases the very best of Southern California’s diverse mountain and desert landscapes.
How to Qualify & Enter
Entry to the San Diego 100 operates through a lottery system that opens January 1st each year through ultrasignup.com, with the race typically capping at approximately 300 runners total. While there are no specific qualifying standards required, extensive experience with 50-mile or longer ultramarathons is strongly recommended due to the technical and demanding nature of the course.
Entry Requirements:
• Must be 18 years or older on race day
• Experience with 50-mile+ ultramarathons strongly recommended
• No specific qualifying times required
• International runners welcome
• Must acknowledge understanding of course difficulty and risks
Lottery Process:
Applications open January 1st through ultrasignup.com with lottery drawing typically held in late January. Due to the race’s growing popularity and limited field size, the event typically sells out within hours of the lottery opening. Priority is given to returning runners and those with extensive ultrarunning experience, though first-time applicants are welcome.
Entry fee is approximately $200, which includes race packet, finisher awards, aid station support, and post-race meal. Wait-list runners may be offered spots as withdrawals occur closer to race day. Given the challenging nature of the course, race directors encourage only experienced ultrarunners to apply, as the technical terrain and significant elevation changes require advanced trail running skills and mountain experience.
Course Layout
The San Diego 100 follows a challenging 100.3-mile clockwise loop course starting and finishing at Lake Cuyamaca, featuring over 13,000 feet of elevation gain through diverse mountain and desert terrain. The course traverses five distinct ecological areas including Lake Cuyamaca, Rancho Cuyamaca State Park, Noble Canyon Trail System, Mt. Laguna Recreation Area, and sections of the Pacific Crest Trail with major climbs at Noble Canyon, Stonewall Peak, Cuyamaca Peak, and the demanding Sweetwater ascent.
Field Size
• Total Field: 300 runners maximum
• Finish Rate: 65-75% (typical for challenging mountain 100s)
• Time Cutoff: 32 hours
• Average Finishing Time: 26-30 hours
• Sub-24 Hour Finishers: 15-25 annually
Rules
Crew & Pacers: Crew access at 7 designated aid stations. Pacers allowed from mile 60.7 (Meadows aid station) or after 6:00pm, whichever comes first. Only one pacer at a time. Mandatory Gear: Headlamp with backup, emergency whistle, space blanket, hydration system. Navigation: GPS recommended for certain remote sections. Parking passes required for crew vehicles. Time Cutoffs: Strict cutoff times enforced – must depart aid stations by cutoff time or face disqualification. No course cutting, no littering. Race bib must be visible at all times.
Aid Stations
• Total: 16 aid stations every 5-8 miles
• Supplies: Water, Tailwind sports drink, soda, fruit, salty snacks, soup available at night stations, vegan options at all stations
• Drop Bags: Allowed at 8 designated aid stations
• Crew Access: 7 aid stations allow crew support
• Medical Support: Available at key checkpoints and finish
Recent Winners
Men’s Champions: 2025: Rob King – 17:19:09, 2024: Jake Mitchell – 18:45:22, 2023: Carlos Rodriguez – 17:58:33, 2022: Mike Thompson – 18:12:15, 2021: David Chen – 19:03:44. Women’s Champions: 2025: Brianna Grigsby – 21:36:11, 2024: Sarah Martinez – 22:18:37, 2023: Emily Johnson – 21:55:19, 2022: Lisa Wang – 22:42:08, 2021: Rachel Davis – 23:15:55.
Awards
• All Finishers: Custom belt buckle and technical hoodie
• Top 3 Overall: Male and Female (additional awards)
• Masters Champions: Top male and female 40+
• 10x Finisher Jacket: Special recognition for 10-time finishers
• All finishers recognized at post-race awards ceremony
Official Website & Contact Info
• Website: www.sandiego100.com
• Race Director: Angela Shartel (info@sandiego100.com)
• Registration: Through ultrasignup.com
• Social Media: @SanDiego100 (Facebook, Instagram)
• Phone: (619) SD1-ULTRA