KEYS100 Ultramarathon
About this race
Registration is open for the 18th Annual race across the islands of the Florida Keys--May 16-17, 2026. This chain of unique and inter-connected islands--some inhabited, some not--end in the City of Key West, just 90 miles from Cuba. This is a pavement race, with approximately 75% run on paved bike paths or sidewalks and the balance on the road shoulder facing traffic. The Florida Keys, known locally as "The Conch Republic", is a spectacular and laid-back sub-tropical paradise, surrounded by the turquoise waters of the Atlantic Ocean and Florida Bay/Gulf of Mexico. The Keys feature great fishing, kayaking, snorkeling and diving, hotels, resorts, B&B's and cuisine and cocktails to fit every budget. There is entertainment to fit every taste, important history and a unique culture, sunsets that will keep you spellbound, special events going on throughout the year including KEYS100, of course, and you don't need a passport to visit here! So, what are you waiting for? We've saved a space for you!
Pick your distance
Running
100 Mile Individual Ultra
Point-to-point running race from Key West Community Park in Key Largo to Key West along the "Florida Keys Overseas Heritage Trail"--Overseas Highway (US #1). 100-milers have 32 hours from the time their wave crosses the start line to complete the race. Each runner MUST have a support crew, but may share a crew with one additional runner who MUST stay within the distance of one published meet-up location of the crew at all times. Runners are self-sufficient; there are no aid stations along the route, although there are staffed timing stations if assistance is needed.
50 Mile Individual Ultra
The 50-mile race is a point-to-point running race from the Marathon Garden Club in Marathon to Key West along the "Florida Keys Overseas Heritage Trail"--Overseas Highway (US #1). 50-milers have 20 hours to complete the race from the time their wave crosses the start line. Each runner MUST have a support crew, but may share a crew with one additional runner who MUST stay within the distance of one published meet-up location of the crew at all times. Runners are self-sufficient; there are no aid stations along the route, although there are staffed timing stations if assistance is needed.
50 Kilometer Individual Ultra
The 50-kilometer race is a point-to-point running race from the Lower Keys Chamber of Commerce property in Big Pine Key to Key West along the "Florida Keys Overseas Heritage Trail"--Overseas Highway (US #1). 50-K runners have 12 hours to complete the course from the time their wave crosses the start line. Each runner MUST have a support crew, but may share a crew with one additional runner who MUST stay within the distance of one published meet-up location of the crew at all times. Runners are self-sufficient; there are no aid stations along the route, although there are staffed timing stations if assistance is needed.
100 Mile Team Relay
Point-to-point running race from Key Largo Community Park in Key Largo to Key West along the "Florida Keys Overseas Heritage Trail"--Overseas Highway (US #1). 100-mile teams have 32 hours to complete the race from the time their first runner crosses the start line. Teams of up to six runners decide their own strategy: runners do not have to run the same number of miles or "legs", nor run in order. Teams are self-sufficient, carrying their own food, water, ice, etc. There are no aid stations along the route, although there are staffed timing stations if assistance is needed.
50 Mile Team Relay
Point-to-point running race from the Marathon Garden Club in Marathon to Key West along the "Florida Keys Overseas Heritage Trail"--Overseas Highway (US #1). 50-mile teams have 20 hours to complete the race from the time their first runner crosses the start line. Teams of up to three runners decide their own strategy: runners do not have to run the same number of miles or "legs", nor run in order. Teams are self-sufficient, carrying their own food, water, ice, etc. There are no aid stations along the route, although there are staffed timing stations if assistance is needed.
Typical race-day weather
Based on 11 years of Open-Meteo archive data for this event's race dates in Key West, plus the 3 days either side.
The sun rises at 6:43 AM and sets at 8:03 PM local time (EDT) in Key West on May 15, 2027 — 13h 20m of daylight.
Course
No course map published yet.
The organizer hasn't released a route for this event, and we don't publish guesses. If you're the organizer, send us a GPX file and we'll draw the profile.
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Results — KEYS100 Ultramarathon
Other races near Key West
Different organizers, within 40 miles, in the next three months
Fantasy Fest 5K Run/Walk
Montessori Key West 5K Run/Walk & Kids Fun Run
Pole Vault in Paradise 5k
2nd Annual Save Our First Responders 5K
🏃 Plan Your Next Race in Key West
Find upcoming events by distance:
- Key West 5K Races 20 races
- 10K Run Events in Key West 5 races
- Key West Half Marathons 2 races
- Key West Running Calendar 2026 25 races
Where this page comes from. Race details were last updated on . We re-check listings regularly and again in the week before race day.
- Entries, prices, waves and inclusions — the event's official registration page
- Temperature and humidity — Copernicus ERA5 reanalysis via Open-Meteo (CC BY 4.0)
- Elevation and terrain relief — Copernicus DEM GLO-90, ESA (CC BY 4.0)
- Comparisons and counts — Race Discovery calendar, 26 Key West events
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