Colorado Triathlon Calendar 2025-2026

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Explore the best triathlons in Colorado for 2025-2026! Our updated list features 338 exciting races across the region. Find your next race in Colorado below and join the running community at these great events!

October 2025
Oct
11
Saturday

Sage Burner Trail Run

Trail Run 15 km 28 km 50 km
Oct
12
Sunday

Westy Half

5 km 13 mi
Oct
12
Sunday

The bRUNch Run

5 km 10 km
Oct
18
Saturday

Indian Creek Trail Runs

Trail Run 5 mi 15 mi 55 km 50 mi
Oct
18
Saturday

The Great Trailhead Foot Race 10 Miler

Trail Run 5 mi 10 mi
Oct
18-19
Sa - Su

Blue Sky Trail Marathon

Trail Run 13 mi 26 mi
Oct
18
Saturday

Bobcat Trail Race

Trail Run 5 km 10 km 25 km 50 km
Oct
18
Saturday

Rabbit Valley Ultras

Trail Run 50 km 100 km
Oct
18
Saturday

The Best Races - Aurora

5 km 10 km 13 mi
Oct
25
Saturday

Foundry Halloween 5k

5 km
Oct
25
Saturday

Beware The Bear Trail Races

Trail Run 5 km 15 km
Oct
25
Saturday

Bridge Burner Ultra

Trail Run 10 km 35 km 50 km 35 mi
Oct
26
Sunday

Ghosts and Goblins 10K

5 km 10 km
November 2025
Nov
1
Saturday

City Park 5k for Pancreatic Cancer Research

5 km 10 km
Nov
1-2
Sa - Su

Colorado 24 Hour Run

Backyard Ultra 6 hr 12 hr 24 hr
Nov
2
Sunday

All-Out Kooky-Spooky

5 km 10 km 13 mi
Nov
2
Sunday

Turkey Trails Denver

5 km 10 km
Nov
2
Sunday

Rim Rock Marathon & Half Marathon

13 mi 26 mi
Nov
2
Sunday

RMRR Trophy Series

5 km 15 km
Nov
2
Sunday

Feet for Justice Run

5 km 10 km
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