
KEYS100 Ultramarathon is a running race on May 15–16, 2027 in Key West, FL, with entry fees from $240 to $1050.
From the Organizer
Registration is open for the 19th Annual race across the islands of the Florida Keys--May 15-16, 2027. 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 and sidewalks, parallel pedestrian bridges and portions of the old service road. The balance is run on the road shoulder facing traffic--and close to it. (Awareness and caution are paramount when running these sections.) 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!
Events
Weather
It's too far out for a forecast, so here's what weather on this date is normally like in the area. A race day forecast will replace this as race week approaches.
Typical High
86°
Typical Low
74°
Chance of Rain
27%
Based on US Climate Normals data from Key W Wfo.
Host City
Population
25,824
as of 2023
City Elevation
3 ft
Nearest Airport
EYW
Key West International Airport · 1 mi
Major Hub
MIA
Miami International Airport · 127 mi
Time Zone
Eastern Time
From Endurance Grid
A mid-size host city. Enough lodging and amenities to keep race weekend easy, without big-city sprawl.
Race Location
Approximate location — pin shows the host city, not the exact venue.
Your Next Start Line
Every finish line starts with a single decision. Claim your spot at KEYS100 Ultramarathon, put it on the calendar, and turn “someday” into a start date.
Plan your trip
Coming from out of town? There's more to Key West than race day. We'll help you line up nearby lodging, flights, a rental car, and things to do so you can make the most of your racecation.
Plan your trip to Key WestComing Up
Hemingway 5K Sunset Run
Less than a mile away
Parrots and Margaritas 5K Run/Walk
1 mile away
Healthy Kids Running Series Fall 2026 - Key West, FL
Less than a mile away
Southernmost Half Marathon and 10K
Less than a mile away
From Endurance Grid
Endurance Grid is here to help you understand the sport, decide if it’s the right fit, and learn how to prepare. For course distances, logistics, and race-day specifics, always defer to the race organizer’s event page.
With running, there's a distance for every fitness level, a community at every start line, and nothing beats the feeling of crossing a finish line you trained for.
Running is an endurance sport that rewards consistency, and showing up every week compounds in ways that will surprise you.
From 5K to marathon, running races are an accessible entry point into endurance sport. There's a distance for every fitness level and a community at every start line.
Frequently Asked Questions (FAQs)
KEYS100 Ultramarathon
May 15, 2027