Event details subject to change. Please confirm all information via event website.

Events Search and Views Navigation

Event Views Navigation

Filters

Changing any of the form inputs will cause the list of events to refresh with the filtered results.

Today

  • Backcountry Marathon

    Rio Grande Park Aspen, CO, United States

    Utilizing the beautiful trails that surround Aspen, and now offering three distances - 50K, marathon and heavy half-marathon, all of which run almost exclusively on dirt trails. For the first […]

  • Sheep Mountain Ultras

    Town of Fairplay Beach Beech Rd, Fairplay, CO, United States

    Make no mistake, the elevation profile for The Sheep Mountain 50 mile and 50k are docile looking. However, the average elevation of over 10,500’ and copious amounts of aggressive terrain, […]

  • PPRR Nielson Challenge

    PPRR Nielson Challenge

    North Monument Valley Park 1794 Culebra Ave., Colorado Springs, CO, United States

    Race Format The first time you run this event, you'll establish a base time for yourself. This base time is used to generate a handicap time. The handicap time is […]

  • Stagecoach Gravel Triathlon

    Stagecoach Reservoir 25500 Co Rd 14, Oak Creek, CO, United States

    We didn't get the chance to launch this race in 2020, but that didn't diminish our passion for this brand new style of triathlon!  To say this race is “unique” […]

  • Boulder Stroke & Stride

    Boulder Stroke & Stride IX

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    The Boulder Stroke & Stride enters its 24th season in 2025, and offers Boulder area athletes a fun 1-lap 750 Meter Swim, or 2-lap 1500 Meter swim in Boulder Reservoir, […]

  • Rocky Mountain Tri-Fest

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    Rocky Mountain Tri-Fest is Colorado's newest Multisport event, catering to the whole family. With events for everyone from mom and dad looking to try their hand at a gravel triathlon, […]

  • Outdoor Divas Triathlon

    Union Reservoir 461 County Road 26, Longmont, CO, United States

    The Outdoor Divas Sprint Triathlon on August 21st, annually awarded best women's event in Colorado by Competitor Magazine, is the all women's triathlon you've been waiting for!  We intentionally keep […]

  • Rock Hawk Trail Race

    Phillip S. Miller Park 1375 West Plum Creek Pkwy, Castle Rock, CO, United States

    Held on the gorgeous, thrilling and rolling trails of Castle Rock’s Miller Park & Ridgeline Trail systems. While not overly technical, these trails will challenge and excite, as you soak […]

  • Boulder Sunset Triathlon

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    Summer may be coming to an end, but our tri season is still heating up! Join us at the Boulder Reservoir for the 13th Annual Boulder Sunset Triathlon, a local […]

  • Boulder Sunset 5K/10K

    Boulder Reservoir 5565 N 51st St, Boulder, CO, United States

    The Boulder Sunset 10K & 5K Run is part of BBSC’s biggest endurance event of the summer. Spend your weekend racing with BBSC at the incredible and scenic Boulder Reservoir. Register, […]

    • Please click here to submit your event for FREE to our online calendar.
    We do not allow events without physical locations (IE – virtual runs, runs with locations TBD, etc…).
    Please allow 48 hours after submission for an event to appear on the calendar. If you have already listed your event and would like us to update it, please contact us.

    Views: 5