Boulder Marathons Events

Boulder Peak Triathlon, Duathlon, & Aquabike

Boulder Reservoir 12 Jul 2026

Boulder Rez Half Marathon

Boulder Reservoir 11 Apr 2026

Colorado Triathlon (Sprint, Olympic, Duathlon, & Aquabike)

Boulder Reservoir 6 Jun 2026

Chelsea Sodaro: An Unlikely Journey to Triathlon, Motherhood, and Ironman World Champion

Chautauqua Community House 18 Mar 2026

Boulder Stroke and Stride Series

Boulder Reservoir 4 Jun 2026

Be Kind to Your Mind 1M 5K 10K 13.1 26.2

Boulder 2 May 2026

Consider the Wildflowers 1M 5K 10K 13.1 26.2

Boulder 1 Mar 2026

2026 Be Brave 1M 5K 10K 13.1 26.2

Boulder 7 Mar 2026

Race for Love 1M 5K 10K 13.1 26.2

Boulder 14 Feb 2026

2026 New Year Challenge -Year of the Horse 2.026 Mile 20.26 Mile 202.6 MILE

Boulder 15 Feb 2026

2026 Taco Sloth 1M, 5K, 10K, 13.1, 26.2

Boulder 22 Feb 2026

Memorial Day 1M 5K 10K 13.1 26.2

Boulder 25 May 2026

2026 First Responders 1M 5K 10K 13.1 26.2

Boulder 28 Mar 2026

Harvest Moon Long Course Triathlon

Boulder Reservoir 31 May 2026

Luck of the Irish 5K

Boulder 17 Mar 2026

2026 The Truth is Out There 1M, 5K, 10K, 13.1, 26.2

Boulder 20 Mar 2026

2026 World Cancer Day 1M 5K 10K 13.1 26.2

Boulder 1 Feb 2026

Mother's Day 1M 5K 10K 13.1 26.2

Boulder 10 May 2026