Colorado
Colorado Triathlon Calendar 2026-2027
Monthly updates for Colorado
Get new running races (and updates) in your inbox every month.
Explore the best triathlons in Colorado for 2026-2027! Our updated list features 12 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!
October 2026
A sprint triathlon in Alamosa, Colorado on October 3, 2026 featuring a 400-yard swim, 10-mile bike and 5k run. Individual and 2- or 3-person team entries, age-group awards and finishers' medals.
A high-altitude ÖTILLÖ swimrun in Fort Collins combining open-water swims in Horsetooth Reservoir with trail runs in Lory State Park across three race distances.
Mini Tri comp only on October 31, 2026 in Fort Lupton features 15 minute swim bike run slots, combined time scoring, and prizes for fastest time and costumes.
February 2027
A winter gravel bike rally and trail run in Lyons, Colorado offering multiple run and ride distances, mixed terrain courses, and a public finish-line party with food and music.
Late February Run, bike, run duathlon at Cherry Creek State Park with two 2.5 mile runs and an 11 mile paved bike course; winter course conditions possible.
Monthly updates for Colorado
Get new running races (and updates) in your inbox every month.
April 2027
A spring race in Breckenridge combining a 6.0 mile bike or run, an ascent to Peak 8 at 12,987' and a downhill finish near Peak 7.
June 2027
IRONMAN 70.3 Boulder is a 70.3 triathlon in Boulder Colorado with a reservoir swim and hilly bike and run courses set against the Flatirons at high elevation.
A three-day high-elevation dirt festival in Alma Colorado featuring mountain bike races, off-road duathlon, trail runs, family kids races and on-site camping.
Two-day Amazing Race style event in South Fork, Colorado with a family day for ages 5 and up and a teams-of-four race featuring varied challenges and cash prizes.
July 2027
High altitude 50 mile trail run in Leadville on July 10, 2027 with about 8,000 feet of elevation gain; registration opens January 7, 2027.
September 2027
Triathlon at Lake Nighthorse in Durango, CO featuring sprint and Olympic distances plus male, female, and coed relays with lake swim, road bike and dirt/gravel run.
A one day team relay in Durango, Colorado combining trail run, mountain bike, road cycling, SUP, open water swim, river paddle and road run.