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KEYS100 Ultramarathon

Date
May 16, 2026
Distance
100 Mile Individual Ultra · 50 Mile Individual Ultra · 50 Kilometer Individual Ultra & more

From the Organizer

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!

Distances & Pricing

100 Mile Individual Ultra5:30 AMRegister →
50 Mile Individual Ultra9 AMRegister →
50 Kilometer Individual Ultra12 PMRegister →
100 Mile Team Relay5 AMRegister →
50 Mile Team Relay9 AMRegister →

Race Location

About This Sport

From Endurance Grid's Founder

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.

The half marathon is the distance where you find out what you're actually made of. Long enough to demand real preparation. Short enough that it doesn't consume your life to train for it. Most people who run their first half describe it as the race that changed their relationship with what they're capable of. Once you cross this finish line, the bar moves. That's not a warning — that's the point.

Race day energy varies by event size, but the finish line feeling is the same regardless. Big races keep the noise going the whole way. Smaller races give you stretches where it's just you and the miles — and that solitude becomes its own kind of fuel.

The half marathon rewards people who show up for the boring training miles.

How long to train: 10–14 weeks. If you're already running consistently, 10 weeks of structured buildup is enough. If you're building from a casual base, give yourself 14.

Running

From 5K to marathon, running races are the most 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)

What is the KEYS100 Ultramarathon?
KEYS100 Ultramarathon is a running event held in Key West, FL. Learn more about the different endurance sports here.
When and where is the KEYS100 Ultramarathon?
Saturday, May 16, 2026 in Key West, FL at Higgs Beach, Key West, FL. Check the official event page for exact start times and wave schedules.
How do I register for the KEYS100 Ultramarathon?
Registration is handled through their official registration page. Confirm pricing, distances available, and sign up there.

KEYS100 Ultramarathon

May 16, 2026

Register →