Racing Underground brings you an amazing half marathon this spring! The Three Creeks Half Marathon features a half marathon course that is flat, fast and scenic! Travel on foot through some of the most beautiful parts of Cherry Creek State Park, with a total combined elevation gain of only 291 feet spread out over 13.1 […]
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 […]
Spring is the season of renewal and running. We hope you join us for a fun adventure that embodies the spirit of springtime at the beautiful Boyd Lake State Park! Choose from the Half Marathon (13.1 mile) or 10K (6.2 mile) for your run adventure. This course is on smooth paved walkways with about three […]
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 […]
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 & […]
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
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 & […]
Presale Registration for 2023 IRONMAN 70.3 Boulder opens at 10am MT on Thursday, August 4, 2022.
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 & […]
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 […]
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 & […]
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 […]
