Colorado Triathlete

Boulder Rez Half
2026-04-11 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
This spring race features a spectator-friendly Half Marathon, 10K and 5K course. Attracting athletes from all over the west due to its phenomenal scenery, glamorous finisher medals, perfect running temperatures with many nearby Boulder attractions to enjoy after the race.
The run course loops around the Boulder Reservoir and remains mostly on dirt trails. The course is flat with only 200 feet of elevation gain. You will experience iconic views of the mountain range to the west.
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The Half Marathon will complete 2 loops, and the 10K will complete one loop. 5K runners will take a different course route.
The Half Marathon is now a USAT Certified Course.

Harvest Moon Long Course Triathlon
2026-05-31 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
The Harvest Moon Half Distance Triathlon: This event takes place at the beautiful Boulder Reservoir on May 31st, 2026 and we couldn’t be more excited to be back for another year. Est. in 2000 this Colorado classic provides the veterans to beginners a challenging, affordable, and competitive race with a local flavor. Whether this is your first event of the season, or a tune-up for a summer long course triathlon, don’t miss the Harvest Moon! The Aquabike portion is one of the fastest growing Aquabikes in the nation, while the duathlon is Colorado’s only long-course duathlon.

Colorado Triathlon
2026-06-06 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
Colorado Sprint Triathlon: 750 meter swim, rolling and fast 17 mile bike, and finishes with a 3.1 mile run
Colorado Olympic Triathlon: 1500m swim, 23.5 mile bike, and a 10k run
Colorado Olympic Duathlon: 5k run, 23.5 mile bike, and a 10k run
Colorado Aquabike: Will feature a 1500 meter swim and a 24.8m bike

Loveland Lake to Lake Triathlon
2026-06-27 | North Lake Park (Loveland), 2750 N. Taft Ave., Loveland, CO, United States
This event provides a beautiful venue. The transition area and lake are near North Lake Park. North Lake Park is a nice setting for competitors and families. It has a children’s train that operates throughout the day and is adjacent to Benson Sculpture Park, which is the site of Loveland’s annual Sculpture in the Park each August.

Boulder Sunrise Triathlon
2026-06-28 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
Kick off your summer of racing in Boulder.

Boulder Peak Triathlon
2026-07-12 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
The Boulder Peak Triathlon, Duathlon & Aquabike on July 10th is one of the countries longest and most well-known triathlons. For the veteran or first time racer, this is THE can’t miss event of the summer triathlon season, and the crown jewel of the Colorado Triathlon Series. Racers are tackling the infamous “Olde Stage” Hill, boasting an average 15% grade on their way to the finish line! This race has earned it’s spot on more than a couple notable “Best Triathlons in America” lists. In 2017, the Boulder Peak was listed as one of the top 15 most amazing triathlons in the United States by The Culture Trip!

Tri Boulder
2026-07-18 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
As one of Colorado’s most popular summer triathlons, Tri Boulder offers many different multisport race distances, all in one eventful day! Join us for a full day of racing at the Rez.

Tri Boulder
2026-08-09 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
Rocky Mountain Tri-Fest was established in 2023 to cater to the whole family. With events for everyone from mom and dad looking to try their hand at a gravel triathlon, to children looking to do their first triathlon.
The Sprint and Super Sprint gravel Tris are beginner friendly with the bike course on the gravel roads surrounding the reservoir. The road are graded and smooth, so you can use almost any bike, even a road bike with wide tires.
The Mini and SSS were created for the younger members of the family, but adults are more than welcome to tag along. These distance take place entirely inside the reservoir, and are 100% about having fun.
We are super excited to be able to offer the kids race for free in 2025. We hope that this will allow more families to join and an introduce this great sport to their children. Use code Rockymountainkids on the USAT membership link to take advantage of a free day license for you children as well.
What bike do you recommend? Do I have to use a “gravel” bike? The simple answer is you can race this course on a mountain bike, on a “gravel” bike, on a cyclocross bike, or even on a road bike with a minimum of 25mm tires and low psi. A tribike and disc wheel would be a little tricky.
For the kids races, anything goes Strider, tricycle, bmx, mountain bike, etc. Please make sure they have a helmet.

Boulder Sunset Triathlon
2026-08-29 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
Join us for an unforgettable morning at the Boulder Reservoir. Although this race does not take place at sunset, it will take place at the end of the summer– it’s sister race is the Boulder Sunrise in June. Experience gorgeous views at the recently upgraded venue. All participants receive stellar race shirts and finisher medals, too. This race is a favorite for beginners due to the flat bike course and a packed dirt trail run course.
