| 331 | 10 Aug 25 | 2025 Cool Sommer Mornings Triathlon & 5K Series #3 | triathlon | Clermont, FL |
| 332 | 13 Jul 25 | 2025 Cool Sommer Mornings Triathlon Series #2 | triathlon | Clermont, FL |
| 333 | 29 Mar 25 | 2025 CORE Indoor Triathlon - Spring | triathlon | Lemont, IL |
| 334 | 13 Jul 25 | 2025 Cornhusker State Games Triathlon | triathlon | Valley, NE |
| 335 | 16 Aug 25 | 2025 Courage Triathlon . . | triathlon | Westwood, CA |
| 336 | 14 Sep 25 | 2025 Craig Ranch McKinney Triathlon | triathlon | McKinney, TX |
| 337 | 27 Jul 25 | 2025 Crescent City Triathlon | triathlon | Crescent, CA |
| 338 | 29 Jun 25 | 2025 Crestwood Kids Triathlon | triathlon | Saint Louis, MO |
| 339 | 26 Jul 25 | 2025 Crofton's Dam Race | triathlon | Crofton, NE |
| 340 | 08 Jun 25 | 2025 Crooked Run Valley 5k/10k | 10K/5K | Delaplane, VA |
| 341 | 13 Apr 25 | 2025 Crow's Nest Triathlon ?? . . | triathlon | Friant, CA |
| 342 | 26 Oct 25 | 2025 Crown Point Marathon/Half-Marathon, Team Relays, 8K & 5K Runs | 5K/8K | San Diego, CA |
| 343 | 04 May 25 | 2025 Crystal Beach Triathlon . . | triathlon | Crystal Beach, TX |
| 344 | 24 May 25 | 2025 Crystal River Triathlon Series - Sprint #1 | triathlon | Crystal River, FL |
| 345 | 07 Jun 25 | 2025 Culpeper Airport 5k | 5K | Culpeper, VA |