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 DateWorld recordChampionship recordRyan Lochte3:55.50Dubai16 December 2010

Results Heats The heats were started at 9:56.Heats results Rank Heat Lane Name Nationality Time Notes 1 4 5 Daiya Seto 4:00.50 Q 2 3 2 Brandonn Almeida 4:04.58 Q 3 2 3 Tomas Peribonio 4:05.08 Q, NR 3 4 3 Thomas Fraser-Holmes 4:05.08 Q 5 4 6 Tomoya Takeuchi 4:05.21 Q 6 4 4 Péter Bernek 4:05.49 Q 7 3 5 Gergely Gyurta 4:06.13 Q 8 3 8 João Vital 4:06.93 Q 9 4 9 Richard Nagy 4:07.91 10 4 1 Joan Lluís Pons 4:08.33 11 3 6 David Schlicht 4:08.41 12 4 7 Marc Sánchez 4:08.51 13 2 6 Kieran Smith 4:08.52 14 2 2 Mark Szaranek 4:08.86 15 4 2 Leonardo Coelho Santos 4:08.93 16 3 3 Daniil Pasynkov 4:09.19 17 2 7 Jarod Arroyo 4:10.40 18 3 0 Patrick Staber 4:11.05 19 3 9 Wang Hsing-Hao 4:11.22 20 3 7 Wang Yizhe 4:11.64 21 4 8 Tomoe Hvas 4:12.56 22 4 0 Ayrton Sweeney 4:13.21 23 2 4 Wilrich Coetzee 4:13.81 24 3 1 Adam Paulsson 4:14.16 25 2 5 Svetlozar Nikolov 4:14.25 26 1 5 Brandon Schuster 4:17.20 27 2 8 Hưng Nguyên Tran 4:17.92 28 2 0 Luis Vega Torres 4:19.27 NR 29 2 9 Erick Gordillo 4:21.02 30 1 3 Munzer Kabbara 4:21.59 NR 31 1 2 Nichita Bortnicov 4:23.08 32 1 4 Malcolm Low 4:25.31 33 2 1 Alberto Batungbacal 4:25.90 34 1 6 Mathieu Marquet 4:33.24 3 4 Wang Shun

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

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

References