2021 FINA World Swimming Championships (25 m) – Women's 800 metre freestyle
# 2021 FINA World Swimming Championships (25 m) – Women's 800 metre freestyle

The Women's 800 metre freestyle competition of the 2021 FINA World Swimming Championships (25 m) was held on 17 and 18 December 2021.

## Records

Prior to the competition, the existing world and championship records were as follows.

| World record | Mireia Belmonte (ESP) | 7:59.34 | Berlin, Germany | 10 August 2013 |
| - | - | - | - | - |
| Competition record | Mireia Belmonte (ESP) | 8:03.41 | Doha, Qatar | 4 December 2014 |

The following new records were set during this competition:

| Date | Event | Name | Nation | Time | Record |
| - | - | - | - | - | - |
| 18 December | Final | Li Bingjie | China | 8:02.90 | CR |

## Results

### Heats

The heats were started on 17 December at 11:14.

| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| - | - | - | - | - | - | - |
| 1 | 3 | 6 | Li Bingjie | China | 8:10.08 | Q |
| 2 | 4 | 8 | Summer McIntosh | Canada | 8:13.37 | Q, WD, NR |
| 3 | 4 | 5 | Isabel Marie Gose | Germany | 8:13.61 | Q |
| 4 | 3 | 4 | Simona Quadarella | Italy | 8:14.10 | Q |
| 5 | 4 | 4 | Anastasiya Kirpichnikova | Russian Swimming Federation | 8:14.53 | Q |
| 6 | 4 | 3 | Martina Caramignoli | Italy | 8:15.01 | Q |
| 7 | 4 | 6 | Katie Grimes | United States | 8:16.01 | Q, WD |
| 8 | 3 | 3 | Anna Egorova | Russian Swimming Federation | 8:17.03 | Q |
| 9 | 3 | 0 | Emma Weyant | United States | 8:20.65 | Q |
| 10 | 3 | 5 | Ajna Késely | Hungary | 8:21.81 | Q |
| 11 | 3 | 7 | Viviane Jungblut | Brazil | 8:24.78 | |
| 12 | 4 | 0 | Viktória Mihályvári-Farkas | Hungary | 8:24.93 | |
| 13 | 3 | 2 | Merve Tuncel | Turkey | 8:25.02 | |
| 14 | 4 | 2 | Beril Böcekler | Turkey | 8:27.79 | |
| 14 | 2 | 4 | María de Valdés | Spain | 8:28.94 | |
| 16 | 2 | 7 | Valentine Dumont | Belgium | 8:29.17 | |
| 17 | 4 | 7 | Diana Durães | Portugal | 8:32.17 | |
| 18 | 3 | 9 | Jimena Pérez | Spain | 8:33.12 | |
| 19 | 4 | 9 | Gabrielle Roncatto | Brazil | 8:33.81 | |
| 20 | 3 | 1 | Ryu Ji-won | South Korea | 8:33.89 | |
| 21 | 4 | 1 | Han Da-kyung | South Korea | 8:34.14 | |
| 22 | 2 | 3 | Lena Opatril | Austria | 8:39.56 | |
| 23 | 2 | 0 | Kamonchanok Kwanmuang | Thailand | 8:39.81 | NR |
| 24 | 2 | 5 | Delfina Dini | Argentina | 8:40.55 | |
| 25 | 2 | 2 | Michaela Pulford | South Africa | 8:41.94 | |
| 26 | 2 | 8 | Arianna Valloni | San Marino | 8:44.10 | NR |
| 27 | 2 | 9 | Zhanet Angelova | Bulgaria | 8:44.88 | |
| 28 | 2 | 6 | Matea Sumajstorčić | Croatia | 8:49.05 | |
| 29 | 1 | 5 | Daniela Alfaro | Costa Rica | 8:56.29 | |
| 30 | 2 | 1 | Eva Petrovska | North Macedonia | 8:59.55 | |
| 31 | 1 | 4 | Michell Ramírez | Honduras | 9:13.03 | |
| | 1 | 3 | Talita Te Flan | Ivory Coast | DNS | |
| | 1 | 6 | Iman Kouraogo | Burkina Faso | DNS | |
| | 3 | 8 | Hou Yawen | China | DNS | |

### Final

The final was held on 18 December at 19:41.

| Rank | Lane | Name | Nationality | Time | Notes |
| - | - | - | - | - | - |
| | 4 | Li Bingjie | China | 8:02.90 | CR |
| | 6 | Anastasiya Kirpichnikova | Russian Swimming Federation | 8:06.44 | |
| | 3 | Simona Quadarella | Italy | 8:07.99 | |
| 4 | 5 | Isabel Marie Gose | Germany | 8:08.26 | |
| 5 | 7 | Anna Egorova | Russian Swimming Federation | 8:14.84 | |
| 6 | 2 | Martina Caramignoli | Italy | 8:17.60 | |
| 7 | 1 | Emma Weyant | United States | 8:20.13 | |
| 8 | 8 | Ajna Késely | Hungary | 8:20.18 | |
