Swimming at the 2015 World Aquatics Championships – Women's 800 metre freestyle
The Women's 800 metre freestyle competition of the swimming events at the 2015 World Aquatics Championships was held on 7 August with the heats and 8 August with the final.
Records
Prior to the championships, the existing world and championship records were as follows.During the competition, prior to this 800 metre event, on 4 August 2015, Katie Ledecky set a new championship record in the 1500 metre freestyle final; her 800-meter mark was at 8:13.25.
| Date | Event | Name | Nationality | Time | Record |
| 4 August | Women's 1500 m freestyle finals | Katie Ledecky | 8:13.25† | CR | |
| 8 August | Final | Katie Ledecky | 8:07.39 | , CR |
Legend: † – en route to final mark
Results
Heats
The heats were held at 11:17| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | 4 | Katie Ledecky | 8:19.42 | Q | |
| 2 | 4 | 5 | Jessica Ashwood | 8:22.17 | Q | |
| 3 | 5 | 6 | Lotte Friis | 8:23.12 | Q | |
| 4 | 5 | 5 | Lauren Boyle | 8:23.66 | Q | |
| 5 | 4 | 4 | Jazmin Carlin | 8:23.83 | Q | |
| 6 | 4 | 6 | Sharon van Rouwendaal | 8:24.83 | Q, NR | |
| 7 | 4 | 2 | Sarah Köhler | 8:26.16 | Q | |
| 8 | 5 | 3 | Boglárka Kapás | 8:26.96 | Q | |
| 9 | 5 | 2 | Leonie Beck | 8:28.39 | ||
| 10 | 4 | 3 | Becca Mann | 8:28.44 | ||
| 11 | 3 | 2 | Kristel Köbrich | 8:33.12 | ||
| 12 | 5 | 8 | Andreina Pinto | 8:33.33 | ||
| 13 | 4 | 7 | Melani Costa | 8:34.89 | ||
| 14 | 5 | 9 | Zhang Yuhan | 8:35.17 | ||
| 15 | 4 | 1 | Jessica Thielmann | 8:36.88 | ||
| 16 | 5 | 7 | Martina Caramignoli | 8:38.56 | ||
| 17 | 4 | 8 | Tjasa Oder | 8:38.85 | ||
| 18 | 3 | 7 | Julia Hassler | 8:39.12 | ||
| 19 | 5 | 1 | Erica Musso | 8:39.55 | ||
| 20 | 2 | 5 | Valerie Gruest | 8:39.88 | ||
| 21 | 3 | 3 | Samantha Arévalo | 8:41.15 | ||
| 22 | 4 | 0 | Beatriz Gómez Cortés | 8:41.72 | ||
| 23 | 2 | 3 | Maria Pugliese | 8:42.14 | NR | |
| 24 | 3 | 0 | Montserrat Ortuño | 8:42.83 | ||
| 25 | 3 | 4 | Cao Yue | 8:43.24 | ||
| 26 | 3 | 5 | Leah Neale | 8:44.38 | ||
| 27 | 4 | 9 | Emma Robinson | 8:44.86 | ||
| 28 | 3 | 9 | Monique Olivier | 8:45.37 | ||
| 29 | 3 | 6 | Joanna Evans | 8:49.96 | ||
| 30 | 2 | 4 | Martina Elhenická | 8:53.08 | ||
| 31 | 2 | 6 | Khoo Cai Lin | 8:55.20 | ||
| 32 | 3 | 1 | Jo Hyun-ju | 8:57.66 | ||
| 33 | 2 | 1 | Daniela Miyahara | 9:00.30 | ||
| 34 | 2 | 2 | Rachel Tseng | 9:01.19 | ||
| 35 | 2 | 7 | Daniella van den Berg | 9:03.71 | ||
| 36 | 2 | 9 | Helena Moreno | 9:09.27 | ||
| 37 | 3 | 8 | Valeriya Salamatina | 9:11.78 | ||
| 38 | 2 | 8 | Hannah Gill | 9:16.23 | ||
| 39 | 2 | 0 | Talita Te Flan | 9:16.89 | ||
| 40 | 1 | 4 | Gabriella Doueihy | 9:18.30 | ||
| 41 | 1 | 5 | Lena Rannvaardottir | 9:35.53 | ||
| 42 | 1 | 3 | Makaela Holowchak | 9:37.68 | ||
| 43 | 1 | 6 | Victoria Chentsova | 9:48.87 | ||
| 5 | 0 | Coralie Balmy | DNS |
Final
The final was held on 8 August at 18:55.| Rank | Lane | Name | Nationality | Time | Notes |
| 4 | Katie Ledecky | 8:07.39 | |||
| 6 | Lauren Boyle | 8:17.65 | OC | ||
| 2 | Jazmin Carlin | 8:18.15 | |||
| 4 | 5 | Jessica Ashwood | 8:18.41 | NR | |
| 5 | 3 | Lotte Friis | 8:21.36 | ||
| 6 | 8 | Boglárka Kapás | 8:22.93 | ||
| 7 | 1 | Sarah Köhler | 8:23.67 | ||
| 8 | 7 | Sharon van Rouwendaal | 8:24.12 | NR |