Boulder Marathons Events

Tri Boulder Sprint, Olympic & Long Course

Boulder Reservoir 18 Jul 2026

Boulder Peak Triathlon, Duathlon, & Aquabike

Boulder Reservoir 12 Jul 2026

Harvest Moon Long Course Triathlon

Boulder Reservoir 31 May 2026

Boulder Sunrise Triathlon

Boulder Reservoir 28 Jun 2026

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

Boulder Reservoir 6 Jun 2026

Boulder Rez Marathon

Boulder Reservoir 15 Aug 2026

Boulder Stroke and Stride Series

Boulder Reservoir 4 Jun 2026

Grit2Greatness Endurance Training Camp 2026 - Boulder, CO

Boulder Reservoir 25 Jun 2026

Just One More Mile Virtual Race 2026 | Global Running Day Virtual

Boulder 3 Jun 2026

Plant Forward Boulder Potluck: Dine with a Dietician

NoBo Library - Boulder Public Library District 21 Jun 2026

Peony Virtual Race | 1M 5K 10K 13.1 26.2 | Language of Flowers Collection

Boulder 30 May 2026

Lavender Virtual Race 1M 5K 10K 13.1 26.2 | Language of Flowers Collection

Boulder 27 Jun 2026

Memorial Day 1M 5K 10K 13.1 26.2

Boulder 25 May 2026

Day of the Dog Virtual Race 1M 5K 10K 13.1 26.2

Boulder 22 Aug 2026

2026 Born to Be a Princess 1M 5K 10K 13.1 26.2 - Now Only $16!

Boulder 1 Nov 2026

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

Boulder 2 May 2026

Face Your Giants Virtual Race 2026 | Christian Virtual Run

Boulder 6 Jun 2026

Cat Day Virtual Race 1M 5K 10K 13.1 26.2

Boulder 9 Aug 2026

Unhinged and Feral 1M 5K 10K 13.1 26.2 - Now Only $18!

Boulder 3 Oct 2026

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

Boulder 10 May 2026

2026 Race to Read 1M 5K 10K 13.1 26.2

Boulder 6 Mar 2026