Ironman 70.3 Boulder

JUN
13
2026
Experience a high altitude triathlon in the shadow of the iconic Flatirons. This event features a reservoir swim, a hilly bike course, and a scenic run through Boulders trails and roads.
Sat 13 Jun 2026
Swim 1.2 Miles Run 13.1 Miles Bike 56 Miles

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IRONMAN 70.3 Boulder

IRONMAN 70.3 Boulder is a triathlon event held in Boulder, Colorado. The competition takes place at high altitude and features a landscape characterized by the Flatirons and the Rocky Mountains. The event provides opportunities for athletes to qualify for the IRONMAN 70.3 World Championship.

The race consists of three segments:

  • Swim: A swim held in the Boulder Reservoir, a local outdoor recreation spot.
  • Bike: A hilly course that travels through the surrounding area.
  • Run: A hilly route that includes Boulder's trails and roads.

The local environment typically sees average high air temperatures of 79 °F (26 °C) and low air temperatures of 61 °F (16 °C). The average water temperature in the reservoir is approximately 71 °F (22 °C).

Participants finish near the vibrant downtown area, including the Pearl Street district. The event is open to individual athletes as well as relay teams. Support services for athletes include access to local TriClubs and an athlete guide. The venue offers various activities for spectators and families. Visit the organization's website for the most recent information.

13 mi
Run 13.1 Miles
Swim 1.2 Miles
Bike 56 Miles