Marathons in Boulder

Check out happening marathons events all around Boulder, CO

Tri Boulder Sprint, Olympic & Long Course

 Sat, 19 Jul, 2025 at 07:15 am Boulder Reservoir

Boulder Sunrise Triathlon

 Sun, 29 Jun, 2025 at 07:15 am Boulder Reservoir

Boulder Rez Half Marathon

 Sat, 12 Apr, 2025 at 08:00 am Boulder Reservoir

Boulder Stroke and Stride Series

 Thu, 05 Jun, 2025 at 06:00 pm Boulder Reservoir

2025 Dash & Dine 5k Run Series

 Tue, 29 Apr, 2025 at 06:30 pm 5565 Reservoir Rd, Boulder, CO, United States, Colorado 80301

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

 Sat, 07 Jun, 2025 at 07:15 am Boulder Reservoir

Boulder Rez Marathon

 Sat, 02 Aug, 2025 at 07:15 am Boulder Reservoir

Boulder Peak Triathlon, Duathlon, & Aquabike

 Sun, 13 Jul, 2025 at 07:15 am Boulder Reservoir

Rev Run Swim Class - WINTER 25

 Fri, 10 Jan, 2025 at 06:00 pm East Boulder Community Center USD 199