in 4 days
The Long View Marathon
Fort Collins, CO625 ft gain
MarathonHalf Marathon+1
Open until Oct 11from $45
5K Races Near Boulder, CO
As of October 6, 2026, Crewable lists 29 upcoming 5K races near Boulder, CO from October 2026 to November 2026. The next is ASDAsh 5K to Beat Tooth Decay on October 10 in Aurora, CO. Registration is open for 27.
Sources: UltraSignup, RunSignUp, UTMB, race organizers and race websites
With aid station data
1 aid
7 aid
3 aid1 aid
Race calendar
October 2026
21 racesCoffee Lovers Run 5K/10K/13.1 DENVER/AURORA
Centennial, COHalf Marathon10K+2Open until Oct 10from $30Halloween Trick or Trot Run 5K/10K/13.1 DENVER/AURORA
Centennial, COHalf Marathon10K+2Open until Oct 31from $30
November 2026
8 racesCity Park Classic (5k/10k & 1 Mile Walk of Hope for Pancreatic Cancer Research)
Denver, CO10K5K+1Open until Nov 7from $23Veterans Day Freedom Run 5K/10K/13.1 DENVER/AURORA
Centennial, COHalf Marathon10K+2Open until Nov 14from $30
Quick answers
What is the next 5K race near Boulder, CO?
ASDAsh 5K to Beat Tooth Decay, on Saturday, October 10, 2026, in Aurora, CO. Distances: 5K.
What is the closest 5K race to Boulder?
Louisville Trail Race in Louisville, CO, about 8 miles from Boulder, on November 14, 2026.
How many 5K races near Boulder, CO have open registration?
27 of the 29 list registration as open as of October 6, 2026, including ASDAsh 5K to Beat Tooth Decay, Breckenridge RunFest and Coffee Lovers Run 5K/10K/13.1 DENVER/AURORA.
What is the busiest month for 5K races near Boulder, CO?
October 2026, with 21 of the 29. November 2026 follows with 8.
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