Colorado
Colorado Triathlon Calendar 2025-2026
Monthly updates for Colorado
Get new running races (and updates) in your inbox every month.
Explore the best triathlons in Colorado for 2025-2026! Our updated list features 8 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!
February 2026
Tackle crisp trails at the Chilly Cheeks Duathlon on Feb 21 2026 at Cherry Creek State Park. This Run Bike Run features short runs and a scenic bike loop on mixed terrain and welcomes fat tire bikes and relays for competition and awards.
April 2026
Take on the Sky Rim Duathlon in Durango on April 18, 2026. Based at Fort Lewis College, this scenic three segment race features a 3 mile run, 12.5 mile bike and a final 3 mile run on college roads and Rim Drive.
June 2026
Take on IRONMAN 70.3 Boulder on June 13, 2026, a World Championship qualifier beneath the Flatirons and Rocky Mountains. A scenic reservoir swim, rolling bike and trail run at high elevation promise stunning views and lively post race atmosphere.
Loveland Lake to Lake Triathlon on June 27, 2026 in Loveland CO offers sprint and Olympic distances plus relay, aqua bike and SUP options. USAT sanctioned with age group and specialty divisions, packet pickup and a Friday Q&A for newcomers.
September 2026
Take on the Lake Nighthorse Triathlon in Durango, Colorado with Sprint, Olympic and Sprint Relay options. Scenic lake swims, climbing bike miles and a rolling dirt and gravel run make for a challenging high altitude race.
Valkyrie Multisport Relay in Durango on Sept 19, 2026 invites teams and solo racers to take on seven stages blending trail run, mountain and road biking, paddleboard, swim, river paddle and road run. Choose full or sprint courses or tackle the Ultra..
Durango's Valkyrie Relay is a scenic multisport team or solo challenge across trails, roads, lakes and the Animas River with full and sprint courses. Teams up to nine or solo Ultra Heptathletes combine running, biking, SUP and paddling.
October 2026
Take part in ÖTILLÖ Swimrun Colorado on October 4, 2026 in Fort Collins and Bellvue, combining open swims in Horsetooth Reservoir with trail runs through Lory State Park. Distances suit both sprint racers and World Series contenders alike.