| 151 | 23 Aug 25 | 2025 Callaway Gardens Olympic Triathlon & Duathlon | triathlon | Pine Mountain, GA |
| 152 | 19 Oct 25 | 2025 CalTri Bearathlon | triathlon | Berkeley, CA |
| 153 | 09 Aug 25 | 2025 Camp Michawana Mini Triathlon #2 | triathlon | Hastings, MI |
| 154 | 20 Dec 25 | 2025 Candy Cane 5k/10k | 10K/5K | Alexandria, VA |
| 155 | 23 Aug 25 | 2025 Capital City Kids Triathlon | triathlon | Lansing, MI |
| 156 | 07 Sep 25 | 2025 Captain Kids Triathlon . . | triathlon | Galveston, TX |
| 157 | 28 Sep 25 | 2025 Captiva Island Triathlon | triathlon | Captiva Island, FL |
| 158 | 20 Sep 25 | 2025 Carderock Charge 5k/10k/Half | 10K/13.1/5K | Potomac, MD |
| 159 | 21 Sep 25 | 2025 Carlyle Lake Triathlon | triathlon | Carlyle Township, IL |
| 160 | 09 Aug 25 | 2025 Cassadaga Kids Triathlon | triathlon | Cassadaga, NY |
| 161 | 04 Oct 25 | 2025 Castle Creek Triathlon | triathlon | Morristown, AZ |
| 162 | 17 Aug 25 | 2025 Cazenovia Triathlon | triathlon | Cazenovia, NY |
| 163 | 04 Oct 25 | 2025 Cedar Creek Park Fall Duathlon | triathlon | Seaford, NY |
| 164 | 07 Aug 25 | 2025 Cedar Lake Triathlon #6 | triathlon | Chester, CT |
| 165 | 27 Sep 25 | 2025 Cedar Mountain Rally 5k/10k | 10K/5K | Orange, VA |