Swimming at the 2017 World Aquatics Championships – Women's 800 metre freestyle
The Women's 800 metre freestyle competition at the 2017 World Championships was held on 28 and 29 July 2017.Records
Prior to the competition, the existing world and championship records were as follows.Results
Heats
The heats were held on 28 July at 11:06.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | 4 | | | 8:20.24 | Q |
| 2 | 3 | 5 | | | 8:21.19 | Q |
| 3 | 4 | 3 | Li Bingjie | | 8:22.92 | Q |
| 4 | 4 | 5 | | | 8:24.98 | Q |
| 5 | 3 | 6 | | | 8:27.70 | Q |
| 6 | 3 | 4 | | | 8:28.93 | Q |
| 7 | 4 | 6 | Zhang Yuhan | | 8:29.52 | Q |
| 8 | 3 | 1 | | | 8:30.66 | Q |
| 9 | 3 | 2 | | | 8:32.01 | |
| 10 | 2 | 4 | | | 8:34.13 | NR |
| 11 | 4 | 8 | | | 8:34.16 | |
| 12 | 3 | 8 | | | 8:34.51 | |
| 13 | 3 | 9 | | | 8:35.10 | |
| 14 | 3 | 3 | | | 8:37.10 | |
| 15 | 4 | 2 | | | 8:38.84 | |
| 16 | 4 | 1 | | | 8:40.68 | |
| 17 | 2 | 3 | Choi Jung-min | | 8:40.87 | |
| 18 | 4 | 7 | | | 8:41.41 | |
| 19 | 4 | 9 | | | 8:41.49 | |
| 20 | 4 | 0 | | | 8:43.93 | |
| 21 | 3 | 0 | | | 8:44.85 | |
| 22 | 3 | 7 | | | 8:44.87 | |
| 23 | 2 | 5 | | | 8:49.76 | |
| 24 | 2 | 7 | | | 8:52.39 | |
| 25 | 2 | 1 | | | 8:54.27 | |
| 26 | 2 | 8 | | | 8:54.30 | |
| 27 | 1 | 4 | | | 8:56.12 | |
| 28 | 2 | 2 | | | 8:56.43 | |
| 29 | 2 | 9 | | | 8:58.31 | |
| 30 | 2 | 0 | | | 9:02.49 | |
| 31 | 1 | 5 | Ho Nam Wai | | 9:03.38 | |
| 32 | 1 | 3 | | | 9:05.67 | |
| 33 | 1 | 7 | | | 9:07.56 | |
| 34 | 2 | 6 | | | 9:08.78 | |
| 35 | 1 | 6 | | | 9:17.77 | |
| 36 | 1 | 1 | | | 9:19.43 | |
| 37 | 1 | 2 | | | 9:32.44 | |
| 38 | 1 | 8 | | | 9:39.78 | |
Final
The final was held on 29 July at 18:55.
| Rank | Lane | Name | Nationality | Time | Notes |
| 4 | Katie Ledecky | | 8:12.68 | |
| 3 | Li Bingjie | | 8:15.46 | AS |
| 5 | Leah Smith | | 8:17.22 | |
| 4 | 6 | Mireia Belmonte | | 8:23.30 | |
| 5 | 7 | Boglárka Kapás | | 8:24.41 | |
| 6 | 1 | Zhang Yuhan | | 8:26.06 | |
| 7 | 2 | Simona Quadarella | | 8:26.50 | |
| 8 | 8 | Holly Hibbott | | 8:38.63 | |
