The men's 400 metre freestyle event at the 2025 World Aquatics Championships was held on 27 July 2025 at the World Aquatics Championships Arena at the Singapore Sports Hub in Kallang, Singapore.
Background Seven of the eight 2024 Paris Olympic finalists were entered into the event. Germany’s Lukas Märtens, fresh from breaking the long-standing 400 freestyle world record in 3:39.96 earlier in the year, was entering as the clear favourite, seeking his first long-course world title in the event. He was joined by Australia’s Elijah Winnington, the 2022 world champion and a 3:41.22 performer, and South Korea’s Kim Woo-min, the 2024 world champion. Australia’s Samuel Short, the 2023 world champion with a 3:40.68 lifetime best, and Brazil’s Guilherme Costa, who broke the Americas record with 3:42.76 in Paris, were also in contention. Newer challengers included American Rex Maurer, ranked third in 2025 with 3:43.33, and Hungary’s Kristóf Rasovszky.
Qualification Each National Federation was permitted to enter a maximum of two qualified athletes in each individual event, but they could do so only if both of them had attained the "A" standard qualification time. For this event, the "A" standard qualification time was 3:48.15. Federations could enter one athlete into the event if they met the "B" standard qualification time. For this event, the "B" standard qualification time was 3:56.14. Athletes could also enter the event if they had met an "A" or "B" standard in a different event and their Federation had not entered anyone else. Additional considerations applied to Federations who had few swimmers enter through the standard qualification times. Federations in this category could at least enter two men and two women to the competition, all of whom could enter into up to two events. +Top 10 fastest qualification timesSwimmerCountryTimeCompetitionLukas Märtens3:39.962025 Malmsten Swim Open StockholmSamuel Short3:41.032025 Australian TrialsElijah Winnington3:41.412024 Australian ChampionshipsKim Woo-min3:42.422024 Mare Nostrum Tour (Monaco)Guilherme Costa3:42.762024 Summer OlympicsOliver Klemet3:42.812024 Gothaer & friends meetFelix Auböck3:43.242024 European ChampionshipsRex Maurer3:43.332025 United States ChampionshipsFei Liwei3:44.242024 Summer OlympicsMarco De Tullio3:44.892025 Sette Colli Trophy
Records Prior to the competition, the existing world and championship records were as follows.
Heats The heats took place at 10:20. Bulgaria's Petar Mitsin won the third heat with the fourth fastest qualifying time of 3:45.01, Australia's Samuel Short won the fourth heat with the fastest qualifying time of 3:42.07, and Germany's Lukas Märtens won the fifth and final heat with the second fastest qualifying time of 3:43.81. Australia's Elijah Winnington and the US's Rex Maurer, along with 2024 Olympic finalists Guilherme Costa and Fei Liwei, did not qualify.
Rank Heat Lane Name Nationality Time Notes 1 4 4 Samuel Short 3:42.07 Q 2 5 4 Lukas Märtens 3:43.81 Q 3 4 5 Kim Woo-min 3:44.99 Q 4 3 7 Petar Mitsin 3:45.01 Q 5 5 1 Zhang Zhanshuo 3:45.04 Q 6 5 9 Victor Johansson 3:45.26 Q, NR 7 4 3 Oliver Klemet 3:45.72 Q 8 5 2 Marco De Tullio 3:45.88 Q 9 3 8 Ethan Ekk 3:46.01 10 5 5 Elijah Winnington 3:46.37 11 5 6 Rex Maurer 3:46.38 12 4 7 Lucas Henveaux 3:46.68 13 5 0 Zalán Sárkány 3:46.82 14 3 6 Jack McMillan 3:47.28 15 3 0 Krzysztof Chmielewski 3:47.55 16 5 8 Daniel Wiffen 3:47.57 17 4 0 Dimitrios Markos 3:47.59 18 4 8 Stephan Steverink 3:47.93 19 3 4 Kazushi Imafuku 3:48.69 20 3 3 Ilia Sibirtsev 3:48.75 21 4 2 Kristóf Rasovszky 3:48.84 22 5 3 Guilherme Costa 3:48.94 23 4 1 David Aubry 3:49.13 24 4 9 Antonio Djakovic 3:49.14 25 4 6 Fei Liwei 3:49.68 26 3 2 Sašo Boškan 3:49.86 27 3 9 Yoav Romano 3:51.01 28 3 5 Khiew Hoe Yean 3:51.11 29 3 1 Juan Morales 3:51.24 30 2 5 Kristupas Trepočka 3:51.34 31 2 3 Milan Vojtko 3:51.97 32 2 7 Glen Lim 3:54.97 33 2 4 Marin Mogić 3:56.15 34 2 1 Gian Santos 3:57.86 35 2 0 Kevin Teixeira 3:59.00 36 5 7 Luka Mijatovic 3:59.68 37 2 6 Aryan Nehra 4:00.39 38 2 8 Suleyman Ismayilzada 4:01.33 39 2 2 Matthew Caldwell 4:01.45 40 2 9 Alberto Vega 4:06.17 41 1 4 Xavier Ventura 4:07.60 42 1 5 Vladimir Hernández Mojarrieta 4:11.70 43 1 3 Binura Thalagala 4:16.80
Final The final took place at 19:02.
Rank Lane Name Nationality Time Notes 5 Lukas Märtens 3:42.35 4 Samuel Short 3:42.37 3 Kim Woo-min 3:42.60 4 7 Victor Johansson 3:44.68 NR 5 2 Zhang Zhanshuo 3:44.82 6 8 Marco De Tullio 3:44.92 7 6 Petar Mitsin 3:45.28 8 1 Oliver Klemet 3:46.86
References