# Swimming at the 2017 World Aquatics Championships – Women's 400 metre freestyle

The Women's 400 metre freestyle competition at the 2017 World Championships was held on 23 July 2017.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Katie Ledecky (USA) | 3:56.46 | Rio de Janeiro, Brazil | 7 August 2016 |
| Competition record | Katie Ledecky (USA) | 3:59.13 | Kazan, Russia | 2 August 2015 |
The following new records were set during this competition.
| Date | Event | Name | Nationality | Time | Record |
| 23 July | Heat | Katie Ledecky | United States | 3:59.06 | CR |
| 23 July | Final | Katie Ledecky | United States | 3:58.34 | CR |

## Results
### Heats

The heats were held at 10:52.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | 4 | Katie Ledecky | United States | 3:59.06 | Q, CR |
| 2 | 3 | 4 | Leah Smith | United States | 4:02.00 | Q |
| 3 | 4 | 3 | Ariarne Titmus | Australia | 4:04.26 | Q |
| 4 | 3 | 5 | Li Bingjie | China | 4:04.94 | Q |
| 5 | 4 | 5 | Boglárka Kapás | Hungary | 4:05.93 | Q |
| 6 | 4 | 6 | Zhang Yuhan | China | 4:06.21 | Q |
| 7 | 4 | 7 | Veronika Popova | Russia | 4:06.40 | Q |
| 8 | 3 | 2 | Ajna Késely | Hungary | 4:06.48 | Q |
| 9 | 3 | 6 | Anja Klinar | Slovenia | 4:07.75 | |
| 10 | 3 | 3 | Mireia Belmonte | Spain | 4:09.55 | |
| 11 | 4 | 0 | Mary-Sophie Harvey | Canada | 4:09.74 | |
| 12 | 4 | 8 | Mackenzie Padington | Canada | 4:09.88 | |
| 13 | 2 | 4 | Diana Duraes | Portugal | 4:10.07 | |
| 14 | 3 | 8 | Joanna Maranhão | Brazil | 4:11.06 | |
| 15 | 4 | 2 | Holly Hibbott | Great Britain | 4:12.77 | |
| 16 | 3 | 0 | Leah Neale | Australia | 4:13.38 | |
| 17 | 2 | 1 | Barbora Závadová | Czech Republic | 4:13.85 | |
| 18 | 4 | 9 | Lee Ea-sop | South Korea | 4:13.94 | |
| 19 | 3 | 1 | Arina Openysheva | Russia | 4:15.45 | |
| 20 | 3 | 9 | Julia Hassler | Liechtenstein | 4:17.05 | |
| 21 | 3 | 7 | Andreina Pinto | Venezuela | 4:17.46 | |
| 22 | 2 | 5 | Monique Olivier | Luxembourg | 4:18.04 | |
| 23 | 2 | 9 | Marina Hansen | Denmark | 4:18.86 | |
| 24 | 2 | 7 | Nicole Oliva | Philippines | 4:19.23 | |
| 25 | 2 | 6 | Helena Moreno | Costa Rica | 4:19.27 | |
| 26 | 2 | 2 | Sze Hang Yu | Hong Kong | 4:20.57 | |
| 27 | 2 | 3 | Kate Beavon | South Africa | 4:20.82 | |
| 28 | 2 | 0 | Hania Moro | Egypt | 4:21.67 | |
| 29 | 2 | 8 | Ressa Dewi | Indonesia | 4:24.05 | |
| 30 | 1 | 3 | Gabriella Doueihy | Lebanon | 4:25.34 | |
| 31 | 1 | 1 | Talita Te Flan | Ivory Coast | 4:26.72 | |
| 32 | 1 | 5 | Sudthirak Watcharabusaracum | Thailand | 4:30.96 | |
| 33 | 1 | 4 | Daniella van den Berg | Aruba | 4:32.09 | |
| 34 | 1 | 6 | Hannah Gill | Barbados | 4:42.55 | |
| 35 | 1 | 7 | Ishani Senanayake | Sri Lanka | 4:45.48 | |
| 36 | 1 | 2 | Victoria Chentsova | Northern Mariana Islands | 4:47.15 | |
| | 4 | 1 | Nguyễn Thị Ánh Viên | Vietnam | DNS | DNS |

### Final

The final was held at 18:03.
| Rank | Lane | Name | Nationality | Time | Notes |
| | 4 | Katie Ledecky | United States | 3:58.34 | CR |
| | 5 | Leah Smith | United States | 4:01.54 | |
| | 6 | Li Bingjie | China | 4:03.25 | |
| 4 | 3 | Ariarne Titmus | Australia | 4:04.26 | |
| 5 | 2 | Boglárka Kapás | Hungary | 4:04.77 | |
| 6 | 8 | Ajna Késely | Hungary | 4:05.75 | |
| 7 | 7 | Zhang Yuhan | China | 4:06.03 | |
| 8 | 1 | Veronika Popova | Russia | 4:07.59 | |