| 301 | 13 Jul 25 | 2025 Cornhusker State Games Triathlon | triathlon | Valley, NE |
| 302 | 16 Aug 25 | 2025 Countryside YMCA Kids Healthy Triathlon - Lebanon | triathlon | Lebanon, OH |
| 303 | 16 Aug 25 | 2025 Courage Triathlon . . | triathlon | Westwood, CA |
| 304 | 14 Sep 25 | 2025 Craig Ranch McKinney Triathlon | triathlon | McKinney, TX |
| 305 | 30 Nov 25 | 2025 Cranberry Crawl Turkey Trot 5k/5-Miler/10M | 10K/13.1/5K | Washington, DC |
| 306 | 27 Jul 25 | 2025 Crescent City Triathlon | triathlon | Crescent, CA |
| 307 | 29 Jun 25 | 2025 Crestwood Kids Triathlon | triathlon | Saint Louis, MO |
| 308 | 26 Jul 25 | 2025 Crofton's Dam Race | triathlon | Crofton, NE |
| 309 | 26 Oct 25 | 2025 Crown Point Marathon/Half-Marathon, Team Relays, 8K & 5K Runs | 5K/8K | San Diego, CA |
| 310 | 26 Jul 25 | 2025 Culpeper Triathlon | triathlon | Culpeper, VA |
| 311 | 07 Aug 25 | 2025 Cupertino Splash & Dash - AUGUST 7 | triathlon | Cupertino, CA |
| 312 | 21 Jun 25 | 2025 Cure Coats' 5K | 5K | San Francisco, CA |
| 313 | 17 Aug 25 | 2025 CVC San Diego Triathlon | triathlon | Chula Vista, CA |
| 314 | 26 Jul 25 | 2025 Cypress Youth Triathlon - SATURDAY ~ Results | triathlon | Cypress, TX |
| 315 | 06 Sep 25 | 2025 Dallas Ft. Worth | 1K/5K | Burleson, TX |