2018 FINA World Swimming Championships (25 m) – Men's 400 metre individual medley
# 2018 FINA World Swimming Championships (25 m) – Men's 400 metre individual medley

The Men's 400 metre individual medley competition of the 2018 FINA World Swimming Championships (25 m) was held on 15 December 2018.

## Records

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

| | Name | Nation | Time | Location | Date |
| - | - | - | - | - | - |
| World record Championship record | Ryan Lochte | United States | 3:55.50 | Dubai | 16 December 2010 |

## Results

### Heats

The heats were started at 9:56.

| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| - | - | - | - | - | - | - |
| 1 | 4 | 5 | Daiya Seto | Japan | 4:00.50 | Q |
| 2 | 3 | 2 | Brandonn Almeida | Brazil | 4:04.58 | Q |
| 3 | 2 | 3 | Tomas Peribonio | Ecuador | 4:05.08 | Q, NR |
| 3 | 4 | 3 | Thomas Fraser-Holmes | Australia | 4:05.08 | Q |
| 5 | 4 | 6 | Tomoya Takeuchi | Japan | 4:05.21 | Q |
| 6 | 4 | 4 | Péter Bernek | Hungary | 4:05.49 | Q |
| 7 | 3 | 5 | Gergely Gyurta | Hungary | 4:06.13 | Q |
| 8 | 3 | 8 | João Vital | Portugal | 4:06.93 | Q |
| 9 | 4 | 9 | Richard Nagy | Slovakia | 4:07.91 | |
| 10 | 4 | 1 | Joan Lluís Pons | Spain | 4:08.33 | |
| 11 | 3 | 6 | David Schlicht | Australia | 4:08.41 | |
| 12 | 4 | 7 | Marc Sánchez | Spain | 4:08.51 | |
| 13 | 2 | 6 | Kieran Smith | United States | 4:08.52 | |
| 14 | 2 | 2 | Mark Szaranek | United Kingdom | 4:08.86 | |
| 15 | 4 | 2 | Leonardo Coelho Santos | Brazil | 4:08.93 | |
| 16 | 3 | 3 | Daniil Pasynkov | Russia | 4:09.19 | |
| 17 | 2 | 7 | Jarod Arroyo | Puerto Rico | 4:10.40 | |
| 18 | 3 | 0 | Patrick Staber | Austria | 4:11.05 | |
| 19 | 3 | 9 | Wang Hsing-Hao | Chinese Taipei | 4:11.22 | |
| 20 | 3 | 7 | Wang Yizhe | China | 4:11.64 | |
| 21 | 4 | 8 | Tomoe Hvas | Norway | 4:12.56 | |
| 22 | 4 | 0 | Ayrton Sweeney | South Africa | 4:13.21 | |
| 23 | 2 | 4 | Wilrich Coetzee | New Zealand | 4:13.81 | |
| 24 | 3 | 1 | Adam Paulsson | Sweden | 4:14.16 | |
| 25 | 2 | 5 | Svetlozar Nikolov | Bulgaria | 4:14.25 | |
| 26 | 1 | 5 | Brandon Schuster | Samoa | 4:17.20 | |
| 27 | 2 | 8 | Hưng Nguyên Tran | Vietnam | 4:17.92 | |
| 28 | 2 | 0 | Luis Vega Torres | Cuba | 4:19.27 | NR |
| 29 | 2 | 9 | Erick Gordillo | Guatemala | 4:21.02 | |
| 30 | 1 | 3 | Munzer Kabbara | Lebanon | 4:21.59 | NR |
| 31 | 1 | 2 | Nichita Bortnicov | Moldova | 4:23.08 | |
| 32 | 1 | 4 | Malcolm Low | Singapore | 4:25.31 | |
| 33 | 2 | 1 | Alberto Batungbacal | Philippines | 4:25.90 | |
| 34 | 1 | 6 | Mathieu Marquet | Mauritius | 4:33.24 | |
| | 3 | 4 | Wang Shun | China | DNS | WD |

### Final

The final was held on 15 December at 20:22.

| Rank | Lane | Name | Nationality | Time |
| - | - | - | - | - |
| | 4 | Daiya Seto | Japan | 3:56.43 |
| | 6 | Thomas Fraser-Holmes | Australia | 4:02.74 |
| | 5 | Brandonn Almeida | Brazil | 4:03.71 |
| 4 | 7 | Péter Bernek | Hungary | 4:04.71 |
| 5 | 1 | Gergely Gyurta | Hungary | 4:04.74 |
| 6 | 3 | Tomas Peribonio | Ecuador | 4:06.26 |
| 7 | 2 | Tomoya Takeuchi | Japan | 4:06.99 |
| 8 | 8 | João Vital | Portugal | 4:07.69 |
