| Rank | Name | Nationality | Time | Heat | Lane | Notes |
| 1 | Rebecca Adlington | | 8:20.53 | 5 | 4 | |
| 2 | Joanne Jackson | | 8:20.80 | 3 | 4 | |
| 3 | Camelia Potec | | 8:22.03 | 4 | 4 | |
| 4 | Alessia Filippi | | 8:24.03 | 5 | 5 | |
| 5 | Lotte Friis | | 8:25.72 | 4 | 5 | |
| 6 | Erika Villaécija García | | 8:26.58 | 5 | 3 | |
| 7 | Wendy Trott | | 8:27.26 | 3 | 3 | |
| 8 | Kristel Köbrich | | 8:27.90 | 3 | 2 | SA |
| 8 | Ophelie-Cyrielle Etienne | | 8:27.90 | 4 | 6 | |
| 10 | Chloe Sutton | | 8:29.25 | 5 | 6 | |
| 11 | Coralie Balmy | | 8:31.39 | 4 | 3 | |
| 12 | Eider Santamaria | | 8:33.51 | 4 | 2 | |
| 13 | Andreina Pinto | | 8:34.17 | 3 | 6 | |
| 14 | Ren Junni | | 8:36.14 | 4 | 1 | |
| 15 | Melissa Gorman | | 8:36.37 | 3 | 7 | |
| 16 | Jordis Steinegger | | 8:36.82 | 5 | 8 | |
| 17 | Patricia Castañeda Miyamoto | | 8:36.98 | 3 | 9 | NR |
| 18 | Blair Evans | | 8:38.10 | 5 | 2 | |
| 19 | Elena Sokolova | | 8:39.09 | 3 | 5 | |
| 20 | Nuala Murphy | | 8:39.17 | 4 | 9 | NR |
| 21 | Maiko Fujino | | 8:40.18 | 5 | 1 | |
| 22 | Gráinne Murphy | | 8:40.23 | 5 | 9 | |
| 23 | Susana Escobar | | 8:41.10 | 4 | 8 | |
| 24 | Lynette Lim | | 8:42.16 | 2 | 2 | |
| 25 | Natsumi Iwashita | | 8:44.43 | 3 | 1 | |
| 26 | Swann Oberson | | 8:44.93 | 2 | 4 | |
| 27 | Yanel Pinto | | 8:45.45 | 2 | 1 | |
| 28 | Haley Anderson | | 8:45.91 | 4 | 7 | |
| 29 | Nina Cesar | | 8:47.51 | 5 | 7 | |
| 30 | Savannah King | | 8:48.01 | 5 | 0 | |
| 31 | Iris Matthey | | 8:49.28 | 2 | 5 | |
| 32 | Yang Chin-Kuei | | 8:49.70 | 2 | 6 | |
| 33 | Nina Dittrich | | 8:51.65 | 3 | 0 | |
| 34 | Erica Cirila Totten | | 8:53.34 | 2 | 8 | NR |
| 35 | Cho Youn Soo | | 8:56.08 | 2 | 7 | |
| 36 | Nika Karlina Petric | | 8:56.71 | 3 | 8 | |
| 37 | Samantha Arevalo | | 9:05.74 | 2 | 0 | |
| 38 | Khoo Cai Lin | | 9:05.77 | 2 | 3 | |
| 39 | Koh Hui Yu | | 9:10.25 | 1 | 5 | |
| 40 | Andrea Cedron | | 9:14.90 | 1 | 4 | |
| 41 | Nada Abbas | | 9:15.62 | 2 | 9 | |
| 42 | Ting Sheng-Yo | | 9:20.80 | 1 | 3 | |
| 43 | Daniela Miyahara Coello | | 9:25.02 | 1 | 6 | |
| 44 | Miriam Hatamleh | | 9:39.87 | 1 | 2 | |
| 45 | Nicole Huerta | | 9:53.98 | 1 | 7 | |
| 46 | Ghulam Sakina | | 10:05.79 | 1 | 1 | NR |
| 47 | Tieri Erasito | | 10:52.89 | 1 | 8 | |
| — | Federica Pellegrini | | DNS | 1 | 0 | |
| — | Paula Zukowska | | DNS | 1 | 9 | |
| — | Tanya Hunks | | DNS | 4 | 0 | |
Rebecca Adlington
Kate Ziegler