| Name | Country | Swim | Bike | Run | Finish | Div. Rank | Overall Rank |
|---|---|---|---|---|---|---|---|
| O'Flanagan, Jason | USA | 00:42:06 | 03:06:00 | 03:51:36 | 07:49:50 | 11 | 663 |
| Obrien, Tim | USA | 00:30:14 | 02:53:47 | 01:54:13 | 05:22:41 | 5 | 182 |
| Oda, Anthony | USA | 00:41:55 | 03:10:06 | 02:42:15 | 06:40:09 | 56 | 487 |
| Ogburn, Maria | USA | 00:43:19 | 03:47:47 | 03:17:24 | 07:58:39 | 19 | 676 |
| Oldfield, Madeleine | USA | 00:26:38 | 02:40:41 | 01:48:44 | 04:58:06 | 12 | 91 |
| Olivas, Melissa | USA | 00:37:38 | 03:05:29 | 02:08:44 | 05:56:39 | 21 | 320 |
| Ortiz, Juan Jose | MEX | 00:31:04 | 03:01:40 | 01:37:34 | 05:17:02 | 18 | 161 |
| Osborne, Wendy | USA | 00:43:09 | 03:18:05 | 02:39:51 | 06:48:45 | 14 | 519 |
| Ossenbrink, Stephanie | CAN | 00:27:27 | 02:47:21 | 01:51:29 | 05:10:00 | 7 | 136 |