| 271 | 07 Sep 25 | 2025 Captain Kids Triathlon . . | triathlon | Galveston, TX |
| 272 | 17 May 25 | 2025 Carderock 5k/10k/Half | 10K/13.1/5K | Potomac, MD |
| 273 | 20 Sep 25 | 2025 Carderock Charge 5k/10k/Half | 10K/13.1/5K | Potomac, MD |
| 274 | 20 Apr 25 | 2025 Care Packages at Carderock 5k/10k/Half | 10K/13.1/5K | Potomac, MD |
| 275 | 21 Sep 25 | 2025 Carlyle Lake Triathlon | triathlon | Carlyle Township, IL |
| 276 | 09 Aug 25 | 2025 Cassadaga Kids Triathlon | triathlon | Cassadaga, NY |
| 277 | 04 Oct 25 | 2025 Castle Creek Triathlon | triathlon | Morristown, AZ |
| 278 | 06 Apr 25 | 2025 CaveMan Triathlon . . | triathlon | Flower Mound, TX |
| 279 | 17 Aug 25 | 2025 Cazenovia Triathlon | triathlon | Cazenovia, NY |
| 280 | 08 Jun 25 | 2025 CB Kids Triathlon | triathlon | Warrington, PA |
| 281 | 04 Oct 25 | 2025 Cedar Creek Park Fall Duathlon | triathlon | Seaford, NY |
| 282 | 05 Apr 25 | 2025 Cedar Creek SPRING Duathlon . . | triathlon | Seaford, NY |
| 283 | 21 Jun 25 | 2025 Cedar Hill Kids & Family Triathlon | triathlon | Cedar Hill, TX |
| 284 | 27 Sep 25 | 2025 Cedar Mountain Rally 5k/10k | 10K/5K | Orange, VA |
| 285 | 11 May 25 | 2025 Cedar River Triathlon | triathlon | Maple Valley, WA |