Annual Races in Boulder

March Races

Lucky Leprechaun 5k

Runners wear green and enjoy post-run food and festivities at a local brewery.

April Races

Boulder Roubaix Road Race

Highly regarded cycling race on an 18.7-mile (30k) loop with 43% paved roads and 57% unpaved roads in north Boulder County.

The Diabetes Link at CU 5K Run/Walk

Run and walk for Type 1 Diabetes research alongside the Juvenile Diabetes Research Foundation and the Children's Diabetes Foundation.

Boulder Rez Half Marathon

Scenic spring race featuring spectator-friendly half-marathon, 10K and 5K courses

May Races

BOLDERBoulder

One of the largest and most highly acclaimed 10Ks in the world, with runners, joggers, walkers and spectators of all ages — many in costume. It's part race, part party, with opportunities to slip-n-slide, do obstacle courses and jam along to garage bands before crossing the finish line in Folsom Field stadium.

Dash & Dine 5K Series

5K at Boulder Reservoir that finishes with dinner from local farms and restaurants.

Frank Shorter Classic 5K

Track meet honoring one of America's greatest distance athletes, Boulder's own Frank Shorter.

The Mother's Day Heart & Sole Half Marathon, 10K & 5K

Mother-daughter and mother-son teams have the chance to win awards.

June Races

Ironman 70.3 Boulder

"Half Ironman" taking place at the Boulder Reservoir. An athlete favorite for over a decade and one of the fastest IRONMAN events to sell out each year.

Colorado Triathlon

Community-oriented event that includes sprint and Olympic distances, duathlon and aquabike options.

Boulder Sunrise Triathlon

Argued to be one of the best and fastest triathlon courses in Colorado.

Summer All-Comer Track & Field Series 

Boulder Road Runners hosts the premier track and field meet series in Colorado for all ages and abilities.

Buffs4Life Kyle MacIntosh Memorial Fun Run

Family event in the CU alumni community with current and former athletes, coaches and fans in support of other Buffs in need of medical assistance.

Sunset Trail Running Festival

A 28K, 12K, 5K and kids' 1K trail race that starts and finishes on the main street of Gold Hill, a mountain community in the Western foothills of Boulder.

July Races

Boulder Peak Triathlon

One of the country's longest and most well-known triathlons and the crown jewel of the Colorado Triathlon Series.

Tri Boulder

One of Colorado’s most popular summer triathlons offering many different multisport race distances at the Boulder Reservoir.

August Races

Boulder Rez Marathon

Run along the Boulder Reservoir on dirt roads and trails with views of the Rocky Mountains.

Rocky Mountain Tri Fest

Events for everyone from mom and dad looking to try their hand at a gravel triathlon, to children looking to do their first triathlon.

Boulder Sunset 10K/5K

BBSC’s biggest endurance event of the summer.

Pearl Street Mile

Criterium multi-lapped course that starts on Spruce St. (between 13th and 14th) and completes 3.75 laps around the Boulder Court House and up the Pearl Street Mall.

September Races

Harvest Moon Triathlon

A Colorado classic providing veterans to beginners with a challenging, affordable and competitive race with local flavor.

Boulderthon

One of the top-rated and most beautiful marathons in the United States.

Buffalo Bicycle Classic

Colorado's largest scholarship fundraising ride.

December Races

ColderBOLDER

The “polar opposite” sister race to BOLDERBoulder, finishing in the University’s field house where festivities and the holiday spirit fill the air.