Running races in Boulder, CO — December 2026

5 races within 25 miles, Tue, Dec 1 – Thu, Dec 31.

Sat Dec 5 time TBC

5K 4.5 mi away hand-checked check the official site for entry Race details

Sat Dec 5 9:00am

5K10KHalf marathon $50 17.6 mi away

Sun Dec 6 9:00am

5K10K15K $40 Westminster, CO

Sat Dec 12 10:00am

5K Superior, CO hand-checked check the official site for entry Race details

Sat Dec 12 10:15am

5K $35 23.1 mi away

Other months in Boulder, CO