KEYS100 Ultramarathon
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Event
KEYS100 Ultramarathon is a point-to-point road race across the islands of the Florida Keys, with the course running from Key Largo to Key West and finishing at Higgs Beach. The 2026 event is scheduled for May 16-17 in Key West, Florida. The course is paved, with approximately 75% on paved bike paths or sidewalks and the remainder on the road shoulder facing traffic. Distances offered include:
- 100 miles (individual and team relay)
- 50 miles (individual and team relay)
- 50 kilometers (individual)
The 50-mile individual and relay start in Marathon; the 50-kilometer individual starts in Big Pine Key. Team relay composition: up to six runners for the 100-mile relay and up to three runners for the 50-mile relay. All races finish at Higgs Beach in Key West.
Participation, support and rules
Individual runners must have a registered support crew; sharing a crew is allowed only when runners remain effectively together. There are no aid stations on the route; runners and teams are expected to be self-sufficient and to use approved meet-up locations for crew support. Each runner or team is allowed only one support vehicle; vehicle size and type restrictions apply and vehicles must be properly marked. Nighttime and visibility requirements include issued reflective wearable identification and required visible lighting when outside the vehicle. IVs and supplemental oxygen are prohibited. Timing mats and course marshals enforce rules; time limits are 32 hours for 100-mile entrants, 20 hours for 50-mile entrants, and 12 hours for 50-kilometer entrants. Visit the organization's website for the most recent information.