# Swimming at the 2019 World Aquatics Championships – Women's 400 metre freestyle

The women's 400-metre freestyle competition at the 2019 World Championships was held on 21 July 2019. Ariarne Titmus overcame a .62-second deficit in the last 50 metres to defeat defending champion Katie Ledecky. This was Ledecky's first loss in a major international 400 metre freestyle competition.

## 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) | 3:58.34 | Budapest, Hungary | 23 July 2017 |

## Results
### Heats

The heats were held at 11:22.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | 4 | Katie Ledecky | United States | 4:01.84 | Q |
| 2 | 4 | 4 | Ariarne Titmus | Australia | 4:02.42 | Q |
| 3 | 4 | 3 | Ajna Késely | Hungary | 4:03.51 | Q |
| 4 | 4 | 5 | Wang Jianjiahe | China | 4:03.97 | Q |
| 5 | 5 | 5 | Leah Smith | United States | 4:04.53 | Q |
| 6 | 4 | 2 | Veronika Andrusenko | Russia | 4:06.28 | Q |
| 7 | 5 | 2 | Boglárka Kapás | Hungary | 4:07.05 | Q |
| 8 | 5 | 7 | Anna Egorova | Russia | 4:07.10 | Q |
| 9 | 5 | 3 | Li Bingjie | China | 4:07.88 | |
| 10 | 5 | 6 | Holly Hibbott | Great Britain | 4:07.92 | |
| 11 | 4 | 6 | Kiah Melverton | Australia | 4:09.56 | |
| 12 | 4 | 8 | Emma O'Croinin | Canada | 4:09.68 | |
| 13 | 3 | 4 | Barbora Seemanová | Czech Republic | 4:09.73 | NR |
| 14 | 3 | 3 | Marlene Kahler | Austria | 4:10.49 | |
| 15 | 4 | 7 | Mireia Belmonte | Spain | 4:10.82 | |
| 16 | 5 | 8 | Joanna Evans | Bahamas | 4:11.06 | |
| 17 | 5 | 0 | Erika Fairweather | New Zealand | 4:12.30 | |
| 18 | 5 | 9 | Valentine Dumont | Belgium | 4:12.92 | |
| 19 | 3 | 6 | Nguyễn Thị Ánh Viên | Vietnam | 4:13.35 | |
| 20 | 5 | 1 | Chihiro Igarashi | Japan | 4:13.81 | |
| 21 | 4 | 0 | Julia Hassler | Liechtenstein | 4:13.91 | |
| 22 | 2 | 4 | Monique Olivier | Luxembourg | 4:14.29 | NR |
| 23 | 3 | 7 | Duné Coetzee | South Africa | 4:14.39 | |
| 24 | 4 | 1 | Mackenzie Padington | Canada | 4:16.06 | |
| 25 | 2 | 6 | Laura Lahtinen | Finland | 4:16.43 | NR |
| 26 | 3 | 5 | Katja Fain | Slovenia | 4:17.57 | |
| 27 | 4 | 9 | Diana Durães | Portugal | 4:17.87 | |
| 28 | 3 | 0 | Gan Ching Hwee | Singapore | 4:17.89 | |
| 29 | 3 | 1 | Elisbet Gámez | Cuba | 4:18.19 | |
| 30 | 2 | 5 | Natthanan Junkrajang | Thailand | 4:19.00 | |
| 31 | 3 | 8 | Nicole Oliva | Philippines | 4:20.03 | |
| 32 | 3 | 2 | Ryu Ji-won | South Korea | 4:21.70 | |
| 33 | 2 | 3 | María Álvarez | Colombia | 4:22.46 | |
| 34 | 2 | 2 | Sara Pastrana | Honduras | 4:27.65 | |
| 35 | 2 | 1 | Amanda Alfaro | Costa Rica | 4:29.91 | |
| 36 | 1 | 3 | Talita Te Flan | Ivory Coast | 4:34.04 | |
| 37 | 2 | 7 | Daila Ismatul | Guatemala | 4:34.75 | |
| 38 | 3 | 9 | Diana Zlobina | Kazakhstan | 4:35.38 | |
| 39 | 2 | 9 | Tiana Rabarijaona | Madagascar | 4:36.73 | |
| 40 | 2 | 0 | Danielle Treasure | Barbados | 4:37.22 | |
| 41 | 2 | 8 | Raya Embury-Brown | Cayman Islands | 4:38.17 | |
| 42 | 1 | 4 | Natalia Kuipers | Virgin Islands | 4:41.69 | |
| 43 | 1 | 5 | Tinatin Kevlishvili | Georgia | 4:49.73 | |

### Final

The final was held at 20:33.
| Rank | Lane | Name | Nationality | Time | Notes |
| | 5 | Ariarne Titmus | Australia | 3:58.76 | OC |
| | 4 | Katie Ledecky | United States | 3:59.97 | |
| | 2 | Leah Smith | United States | 4:01.29 | |
| 4 | 3 | Ajna Késely | Hungary | 4:01.31 | NR |
| 5 | 6 | Wang Jianjiahe | China | 4:03.67 | |
| 6 | 1 | Boglárka Kapás | Hungary | 4:05.36 | |
| 7 | 8 | Anna Egorova | Russia | 4:06.16 | |
| 8 | 7 | Veronika Andrusenko | Russia | 4:08.60 | |