Horsetooth Open Water Swim takes place on Sun, Sep 13, 2026 in Fort Collins, United States. The main route is 10 km.
- Date
- Sun, Sep 13, 2026
- Start
- Fort Collins 🇺🇸
- Distance
- 10 km
- Level
- Open to all
The Horsetooth Open Water Swim is a high-altitude open water event held at 5,430 feet in the Horsetooth Reservoir in Fort Collins, Colorado.
Official event pageWhat this race demands
The Horsetooth Open Water Swim demands sustained high-altitude aerobic endurance across a 10 km open water distance.
Altitude adaptation
Athletes must manage the physiological stress of competing at an elevation of 5,430 feet in Fort Collins, Colorado.
Endurance capacity
The 10 km swimming distance requires advanced pacing strategies and extensive physical durability to sustain effort over an extended duration.
Open water navigation
Participants must maintain efficient sighting and stroke mechanics in a reservoir environment without lane lines.
Given the extended duration of a 10 km swim, athletes should target 60 to 90 grams of carbohydrates per hour through liquid or easily digestible nutrition managed via support craft or feed stations.
Your road to race day
Race day at Horsetooth Open Water Swim is 3 weeks away. This is how a coach divides that time. The first phase starts now.
01Taper2 weeks · Aug 24, 2026 – Sep 6, 2026
Volume drops while intensity stays: short, sharp efforts keep the legs awake as fatigue drains away.
02Race week1 week · Sep 7, 2026 – Sep 13, 2026
Openers, rest and logistics. The work is done; the job now is arriving fresh.
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