# Swimming at the 2023 World Aquatics Championships – Men's 400 metre freestyle

The men's 400 metre freestyle competition at the 2023 World Aquatics Championships was held on 23 July 2023.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Paul Biedermann (GER) | 3:40.07 | Rome, Italy | 26 July 2009 |
| Competition record | Paul Biedermann (GER) | 3:40.07 | Rome, Italy | 26 July 2009 |

## Results
### Heats

The heats were started at 10:47.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 6 | 4 | Samuel Short | Australia | 3:42.44 | Q |
| 2 | 6 | 3 | Felix Auböck | Austria | 3:44.14 | Q |
| 3 | 5 | 5 | Guilherme Costa | Brazil | 3:44.17 | Q |
| 4 | 5 | 7 | Ahmed Hafnaoui | Tunisia | 3:44.34 | Q |
| 5 | 5 | 4 | Lukas Märtens | Germany | 3:44.42 | Q |
| 6 | 6 | 2 | Kim Woo-min | South Korea | 3:44.52 | Q |
| 7 | 6 | 5 | Elijah Winnington | Australia | 3:44.63 | Q |
| 8 | 5 | 3 | Antonio Djakovic | Switzerland | 3:45.43 | Q |
| 9 | 5 | 2 | Kieran Smith | United States | 3:45.77 | |
| 10 | 6 | 0 | Kristóf Rasovszky | Hungary | 3:46.56 | |
| 11 | 5 | 0 | Alfonso Mestre | Venezuela | 3:46.61 | NR |
| 12 | 6 | 6 | Marco De Tullio | Italy | 3:47.23 | |
| 13 | 5 | 1 | Lucas Henveaux | Belgium | 3:47.88 | |
| 14 | 6 | 1 | Matteo Ciampi | Italy | 3:48.12 | |
| 15 | 5 | 8 | Marwan Elkamash | Egypt | 3:48.31 | |
| 16 | 4 | 7 | Kregor Zirk | Estonia | 3:48.43 | |
| 17 | 6 | 7 | David Johnston | United States | 3:48.68 | |
| 18 | 4 | 5 | Bar Soloveychik | Israel | 3:49.21 | |
| 19 | 4 | 2 | Dimitrios Markos | Greece | 3:49.41 | |
| 20 | 4 | 1 | Carlos Quijada | Spain | 3:49.60 | |
| 21 | 5 | 6 | Oliver Klemet | Germany | 3:49.79 | |
| 22 | 4 | 6 | Krzysztof Chmielewski | Poland | 3:49.90 | |
| 23 | 4 | 8 | Eric Brown | Canada | 3:50.68 | |
| 24 | 4 | 3 | Khiew Hoe Yean | Malaysia | 3:50.78 | |
| 25 | 6 | 8 | Logan Fontaine | France | 3:51.56 | |
| 26 | 4 | 4 | Luke Turley | Great Britain | 3:51.95 | |
| 27 | 4 | 0 | Jovan Lekić | Bosnia and Herzegovina | 3:53.17 | |
| 28 | 3 | 6 | Joaquín Vargas | Peru | 3:53.54 | |
| 29 | 3 | 2 | Eduardo Cisternas | Chile | 3:53.80 | NR |
| 30 | 3 | 5 | Velimir Stjepanović | Serbia | 3:54.25 | |
| 31 | 4 | 9 | Glen Lim Jun Wei | Singapore | 3:54.42 | |
| 32 | 6 | 9 | Zac Reid | New Zealand | 3:55.55 | |
| 33 | 5 | 9 | Zhang Ziyang | China | 3:55.76 | |
| 34 | 3 | 1 | Tonnam Kanteemool | Thailand | 3:56.69 | |
| 35 | 3 | 3 | Kushagra Rawat | India | 3:59.03 | |
| 36 | 3 | 4 | Đỗ Ngọc Vĩnh | Vietnam | 4:02.05 | |
| 37 | 3 | 7 | Pavel Alovatki | Moldova | 4:02.43 | |
| 38 | 3 | 0 | Loris Bianchi | San Marino | 4:03.88 | |
| 39 | 2 | 3 | Sauod Al-Shamroukh | Kuwait | 4:04.95 | |
| 40 | 2 | 8 | Gerald Hernández | Nicaragua | 4:05.13 | NR |
| 41 | 2 | 4 | Alberto Vega | Costa Rica | 4:05.18 | |
| 42 | 1 | 6 | Raekwon Noel | Guyana | 4:05.70 | |
| 43 | 2 | 5 | Théo Druenne | Monaco | 4:06.58 | NR |
| 44 | 1 | 4 | Mal Gashi | Kosovo | 4:07.65 | |
| 45 | 2 | 6 | Nikola Ǵuretanoviḱ | North Macedonia | 4:07.87 | |
| 46 | 2 | 0 | Nasir Yahya Hussain | Nepal | 4:08.23 | NR |
| 47 | 2 | 7 | Líggjas Joensen | Faroe Islands | 4:09.17 | |
| 48 | 2 | 9 | Timothy Leberl | Mauritius | 4:09.47 | |
| 49 | 2 | 1 | Mauricio Arias | Dominican Republic | 4:11.15 | |
| 50 | 1 | 5 | Muhammad Siddiqui | Pakistan | 4:12.29 | NR |
| 51 | 2 | 2 | José Campo | El Salvador | 4:15.97 | |
| 52 | 3 | 9 | Dylan Cachia | Malta | 4:16.27 | |
| 53 | 1 | 2 | Ali Al-Awi | Bahrain | 4:17.02 | NR |
| 54 | 1 | 3 | Mohammed Al-Zaki | Saudi Arabia | 4:20.48 | |
| 55 | 3 | 8 | Mark Ducaj | Albania | 4:20.88 | |

### Final

The final was started at 20:02.
| Rank | Lane | Name | Nationality | Time | Notes |
| | 4 | Samuel Short | Australia | 3:40.68 | |
| | 6 | Ahmed Hafnaoui | Tunisia | 3:40.70 | AF |
| | 2 | Lukas Märtens | Germany | 3:42.20 | |
| 4 | 3 | Guilherme Costa | Brazil | 3:43.58 | |
| 5 | 7 | Kim Woo-min | South Korea | 3:43.92 | |
| 6 | 8 | Antonio Djakovic | Switzerland | 3:44.22 | |
| 7 | 1 | Elijah Winnington | Australia | 3:44.26 | |
| 8 | 5 | Felix Auböck | Austria | 3:44.43 | |