| 241 | 05 Oct 25 | 2025 Cohutta Triathlon | triathlon | Crandall, GA |
| 242 | 08 Aug 25 | 2025 Columbia River Kids Triathlon & All Age Sunset Run 5K & 10K - Friday | triathlon | Vancouver, WA |
| 243 | 09 Aug 25 | 2025 Columbia River Triathlon | triathlon | Vancouver, WA |
| 244 | 14 Sep 25 | 2025 Cool Sommer Mornings Sprint Triathlon, Duathlon & 5K #4 | triathlon | Clermont, FL |
| 245 | 10 Aug 25 | 2025 Cool Sommer Mornings Triathlon & 5K Series #3 | triathlon | Clermont, FL |
| 246 | 18 Oct 25 | 2025 Coronado Heights Run | 5K/15K | Lindsborg, KS |
| 247 | 16 Aug 25 | 2025 Countryside YMCA Kids Healthy Triathlon - Lebanon | triathlon | Lebanon, OH |
| 248 | 16 Aug 25 | 2025 Courage Triathlon . . | triathlon | Westwood, CA |
| 249 | 14 Sep 25 | 2025 Craig Ranch McKinney Triathlon | triathlon | McKinney, TX |
| 250 | 30 Nov 25 | 2025 Cranberry Crawl Turkey Trot 5k/5-Miler/10M | 10K/13.1/5K | Washington, DC |
| 251 | 31 Aug 25 | 2025 CRC Labor Day Weekend 10K & 5K | 5K/10K | Fort Worth, TX |
| 252 | 27 Nov 25 | 2025 CRC Thanksgiving Day 13.1, 6.2, 3.1 & Fun Run/Walk | 5K/10K | Fort Worth, TX |
| 253 | 27 Jul 25 | 2025 Crescent City Triathlon | triathlon | Crescent, CA |
| 254 | 26 Jul 25 | 2025 Crofton's Dam Race | triathlon | Crofton, NE |
| 255 | 26 Oct 25 | 2025 Crown Point Marathon/Half-Marathon, Team Relays, 8K & 5K Runs | 5K/8K | San Diego, CA |