IRONMAN 70.3 Cozumel
Cozumel, Mexico · usually held in September
Ocean swim · wetsuits usually not allowed
About 0 m of climbing per km — a flat course by our rule of thumb.
Hot or humid conditions
IRONMAN 70.3 Cozumel is a Half / 70.3 triathlon in Cozumel, Mexico, usually held in September. Below is what the official race information says about the swim, the bike course and the conditions, and what that means for your gear and fueling.
Racing it
The swim
The swim is in the sea. The race lists an average water temperature of about 29°C (84°F). The race lists the swim as not wetsuit legal, so plan to swim in your tri suit or a swimskin.
The bike
The race lists about 0 m (0 ft) of climbing on the bike course. That’s about 0 m per km, flat by our rule of thumb: aero bars and a steady position pay off.
Conditions and fueling
The race lists an average air temperature of about 33°C (91°F). By our rule of thumb that’s hot or humid: plan extra fluid and sodium with the Race Nutrition Calculator, and practise drinking on the bike.
FAQ
Is IRONMAN 70.3 Cozumel wetsuit legal?
The race lists the swim as not wetsuit legal, so plan on a tri suit or swimskin.
How warm is the water at IRONMAN 70.3 Cozumel?
The race lists an average water temperature of about 29°C (84°F). It varies year to year, so check the official update in race week.
Is the IRONMAN 70.3 Cozumel bike course hilly?
The race lists about 0 m (0 ft) of climbing. That’s about 0 m per km, flat by our rule of thumb: aero bars and a steady position pay off.
Your race, tool by tool
Plan to swim without a wetsuit
Typical water temperature is in our “warm” band: check the race’s wetsuit rule, and consider a sleeveless suit or swimskin.
Aero pays on a flat course
You’ll spend most of the ride on the aero bars, so position and aerodynamics are worth the most here.
Clip-ons or tri bike? →70g carbs · 900mg sodium · 950ml fluid an hour
Calculated for a mid-pack, average-sweat 70–80 kg athlete in these conditions (finish around 5:34). Make it yours in the calculator.
Personalise my fuel plan →Race checklist, pre-filled
Distance, swim and forecast already set for this race.
Open my checklist →Conditions are typical, not a forecast. Wetsuit rules, course and aid stations can change: always check the official athlete guide.
Sources: www.ironman.com · water temperature: https://www.ironman.com/races/im703-cozumel · facts checked 2026-11-02