Colorado Triathlete

XTERRA Lory
2026-06-20 | Lory State Park (Fort Collins), 708 Lodgepole Drive, Bellvue, CO, 80512, United States
XTERRA Lory Triathlon on June 18th is the perfect kick-off to the year for the seasoned off-road triathlete, or a great opportunity for the road triathlete wanting to try out a mountain bike triathlon for the first time.
The XTERRA Lory Triathlon features a 1/2 mile swim in the clear waters of Horsetooth Reservoir (Eltuk Bay), it’s one of the most scenic swims in the state with canyon walls on both sides. Then it’s on to a 2-Lap (beginner friendly) 12.2 mile single-track bike over rolling terrain, and across valley bridges at Lory State Park. Then you’ll get to finish things off with a fun and challenging 4.8 mile (8k) run through the clouds on single-track trails! This is the perfect off-road triathlon for beginners to experts. The course is designed so that anyone can have fun and everyone will be challenged! Entries will be limited to 350 participants, and we sold out 2011-2021 in early April!
BACK FOR 2022: Stand Up Paddleboard Option instead of the 1/2 mile swim (you must bring your own SUP)!

Stroke & Stride
2026-06-25, 2026-07-09, 2026-07-16, 2026-07-23, 2026-07-30, 2026-08-06 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
The Boulder Stroke & Stride offers Boulder area athletes a fun 1-lap 750 Meter Swim, or 2-Lap 1500 Meter swim in Boulder Reservoir, followed by a 5k run on the reservoir dam on 8 Thursday evenings (plus one Wednesday evening) throughout the summer. Many participants make their open-water swimming debut in the beginner-friendly Stroke & Stride 750 meter event, while more seasoned athletes get the thrill of starting alongside some of the top athletes in the world in the 1,500 meter swim. 250-400 participants enjoy the Stroke & Stride every week! Live timing, great post race food, beanie for 6-pack entries, and series prizes are just the beginning!

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.

Timberview Trail Run
2026-06-27 | Boyd Lake State Park (Loveland), 3720 N County Road 11-C, Loveland, CO, 80538, United States
Crisp morning air and a summer sunrise in Colorado. YES PLEASE! Join us on the foothills at Lory State Park for a fun & beautiful morning trail race experience.
This run race features three distances (a 10 mile, a 5 mile and a 5K) that are great for just about any level athlete at any age. Run on a beautiful & scenic course among the treetops with views of Horsetooth reservoir, Fort Collins & the foothills. Bring the kiddos too as the 5K route is very beginner friendly.

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

The Blue Sky Ascent
2026-06-28 | Idaho Springs, Idaho Springs, United States
Although the air will be noticeably thin at the starting line, Echo Lake’s 10,600 feet of elevation is just the beginning. The climb totals nearly 4,000 vertical feet – much of it above treeline – as you make your way 14.5 miles to the finish line located at the summit of one of the most recognizable peaks on Denver’s mountain skyline – 14,264 foot Mt. Blue Sky.
Be inspired!!!
Join us for another memorable run. Spectators will include Bighorn Sheep, Marmots, and Mountain Goats – maybe even a few people!!!

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.

Steamboat Lake Triathlon
2026-07-26 | Steamboat Lake State Park, 61105 County Road 129, Clark, CO, 80428, United States
After last summer this event instantly became a personal favorite for our staff, volunteers, and athletes – come find out why! We couldn’t be more excited about this course, this lake, and the overall experience. The swim starts out in the surprisingly warm waters of Steamboat Lake (74 degrees average race temp), then athletes transition to the most scenic bike course you’ll ever find. You’re more likely to see a herd of cattle crossing the road than be passed by a vehicle! After a ride through the rolling country-side athletes will transition to a 3.5 mile run course that’s 50% on road, and 50% on the dirt trails that hug the lakeside. When we tell athletes you’re running through wild flower meadows, we’re not exaggerating.
Pack the camping gear and make a weekend getaway for your all your friends and family! This year we’re also offering a aquabike, and stand-up paddle-board division!

Stagecoach Gravel Triathlon
2026-08-02 | Stagecoach Reservoir (Steamboat Springs), 25500 County Road 14, Oak Creek, CO, 80467, 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” would be an understatement! Limited to just 250 athletes, we’re excited to announce the first ever gravel triathlon to the Colorado triathlon landscape! This event is set at Stagecoach Reservoir, a quiet and picturesque lake just 15min south of Steamboat Springs, with camping options for the entire family.
After the swim in the waters of Stagecoach Reservoir, it’s time to bring out either the gravel bike, road bike, or mountain bike. Just leave your triathlon bike at home. The course starts out with a short-paved section of 2.1 miles, before transitioning to rolling gravel country roads through some of the most scenic terrain imaginable. The total bike distance is 16 miles, with the final 3 miles of the course on pavement as athletes head back towards the transition area! Once off your bike of choice, it’s time to toss on those running shoes for a 4-mile run on a gravel trail that hugs the shoreline of Stagecoach Reservoir, (Note: ½ mile total on paved roads)! Come join us for this one of a kind triathlon experience, complete with a stand-up paddle-board option for the non-swimmers!

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 Rez Marathon
2026-08-15 | Boulder Reservoir, 5275 Reservoir Road, Boulder, CO, 80301, United States
This amazing run course will take you alongside the Boulder Reservoir, remaining mostly on dirt roads and trails. The course is flat with only 200 feet of gain, and will provide views of the Boulder Reservoir and Rocky Mountains.

Outdoor Divas Sprint Triathlon
2026-08-16 | Union Reservoir (Longmont), 461 County Road 26, 80504, United States
The Outdoor Divas Sprint Triathlon features a half mile lake swim, a flat and fast single loop 12.4 mile bike, and finishes with a 3.1 mile run on a gravel road that hugs the lake.

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.

Littlefoot Triathlon
2026-09-12 | Bear Creek Lake Park (Lakewood), 15600 W. Morrison Road, Lakewood, CO, 80228, United States
Enjoy a fun late season tri at beautiful Bear Creek Lake Park in the Lakewood/Morrison area. Set at the base of the foothills, the Littlefoot Triathlon starts off with a 750 meter swim in Soda Lake, with water temps expected to be approximately 70 degrees. Next, a rolling bike 15K bike ride that covers nearly the entire park, offering great views throughout! Finish it up with a scenic 5K run on a bike path that winds through the park.

Oktoberfest Sprint Triathlon
2026-09-20 | Union Reservoir (Longmont), 461 County Road 26, 80504, United States
The Oktoberfest Sprint Triathlon features a half mile lake swim, a flat and fast single loop 12.9 mile bike, and finishes with a 3.1 mile run on a gravel road that hugs the lake. Please see course maps for a full description. Overall this is a beginner friendly course, and sets up very well for family and friends to spectate right alongside the action. The best part of Union Reservoir is how close the transition area, start line, finish line, expo area, and parking are to each other!

Last Call Triathlon
2026-09-27 | Boyd Lake State Park (Loveland), 3720 N County Road 11-C, Loveland, CO, 80538, United States
Yes! I want ONE MORE adventure!! Escape to the lake! The Last Call Triathlon will be an event you’ll look forward to all season long. Why? Beautiful mountain views, great weather and a family fun venue! Did we mention camping? Yup! There’s that too. Sitting on the east side of Loveland and southeast of Fort Collins, this close-to-home race day will have a family feel that’s intimate, fun and uniquely challenging. The course layouts make race morning packed with spectator cheering and multiple athlete flybys. With ON-SITE camping options, make a weekend out of this event and plan some extra relaxation time.

Narrowleaf Lake Run
2026-10-31 | Boyd Lake State Park (Loveland), 3720 N County Road 11-C, Loveland, CO, 80538, United States
Brisk autumn running in Colorado – OH YEA! Join us for a family fun event with FIVE distance options at the beautiful Boyd Lake State Park venue.
Choose your adventure! Heavy 5K, 10K, 15K (4, 7 or 10 mile) or 1 Mile Pumpkin race options. There is also a Kid’s Fun Run (1 & 1/2 mile options) as well!
This course is on perfectly paved walkways with about a half mile being off road on the south loop. Beautiful lake and wildlife views, NO vehicle traffic to worry about and fun post race festivities. Did we mention almost no elevation gain? This is one flat course making sure you’ll set a new PR or enjoy a fun steady-paced morning run race.
What’s a “Narrowleaf”?? The Narrowleaf Cottonwood Trees are the most densely populated tree species at Boyd Lake State park. We thought the name was fitting and unique to this venue.
