| 271 | 22 Jun 25 | 2025 Chattanooga Waterfront Triathlon | triathlon | Chattanooga, TN |
| 272 | 26 Jul 25 | 2025 Chesaning Chamber of Commerce Dry-Tri | triathlon | Chesaning, MI |
| 273 | 25 Oct 25 | 2025 Chessie Trail Marathon, Half Marathon, 10K, 5K, & 26.2 Relay | 10K/13.1/26.2/5K | Lexington, VA |
| 274 | 21 Jun 25 | 2025 Chesterfield Youth Triathlon | triathlon | Chesterfield, MO |
| 275 | 23 Aug 25 | 2025 Chicago Triathlon (Sunday) | triathlon | Chicago, IL |
| 276 | 16 Aug 25 | 2025 Chick-fil-A Cherokee County 5K | 5K | Canton, GA |
| 277 | 01 Aug 25 | 2025 Chile Harvest YOUTH Triathlon - FRIDAY | triathlon | Socorro, NM |
| 278 | 26 Jul 25 | 2025 Chisago Lakes Kids Triathlon - Saturday | triathlon | Chisago, MN |
| 279 | 27 Jul 25 | 2025 Chisago Lakes Triathlon - Sunday | triathlon | Chisago, MN |
| 280 | 24 Dec 25 | 2025 Christmas Eve 5k/10k | 10K/5K | Washington, DC |
| 281 | 26 Jul 25 | 2025 Christmas in July 5k/Half | 13.1/5K | Washington, DC |
| 282 | 06 Sep 25 | 2025 Chroma Team Racing Championship . . | triathlon | Nashville, TN |
| 283 | 01 Sep 25 | 2025 Cincinnati Aruna Run | 10K/1M/5K | Cincinnati, OH |
| 284 | 10 Aug 25 | 2025 Classic City Sprint, Duathlon and Aquabike | triathlon | Athens, GA |
| 285 | 28 Jun 25 | 2025 Claude Moore 5k/10k | 10K/5K | Sterling, VA |