2012 FINA World Swimming Championships (25 m) – Men's 400 metre freestyle
The men's 400 metre freestyle event at the 11th FINA World Swimming Championships took place 14 December 2012 at the Sinan Erdem Dome.
In June 2013, Danish swimmer Mads Glæsner was stripped of the bronze medal after testing positive for levomethamphetamine.Records
Prior to this competition, the existing world and championship records were as follows.
No new records were set during this competition.Results
Heats
| Rank | Heat | Lane | Name | Time | Notes |
| 1 | 6 | 4 | | 3:41.07 | Q |
| 2 | 6 | 2 | | 3:41.34 | Q |
| 3 | 5 | 5 | | 3:41.40 | Q |
| 4 | 6 | 3 | | 3:41.59 | Q |
| 5 | 7 | 8 | | 3:41.80 | Q |
| 6 | 1 | 7 | | 3:42.13 | Q |
| 7 | 5 | 4 | | 3:42.43 | Q |
| 8 | 5 | 3 | | 3:42.49 | |
| 9 | 7 | 0 | | 3:42.76 | |
| 10 | 6 | 5 | | 3:42.97 | |
| 11 | 7 | 3 | | 3:43.05 | |
| 12 | 6 | 6 | | 3:43.29 | |
| 13 | 7 | 6 | | 3:43.52 | |
| 14 | 5 | 7 | | 3:43.70 | |
| 15 | 5 | 2 | | 3:43.88 | |
| 16 | 7 | 5 | | 3:44.09 | |
| 17 | 6 | 9 | | 3:44.22 | |
| 18 | 7 | 7 | | 3:44.46 | |
| 19 | 7 | 2 | | 3:44.56 | |
| 20 | 5 | 0 | | 3:45.77 | |
| 21 | 5 | 6 | | 3:46.00 | |
| 22 | 6 | 1 | | 3:47.19 | |
| 23 | 6 | 8 | | 3:47.56 | |
| 24 | 4 | 2 | | 3:47.83 | NR |
| 25 | 7 | 9 | | 3:48.29 | |
| 26 | 4 | 4 | | 3:48.56 | NR |
| 27 | 4 | 5 | | 3:48.62 | |
| 28 | 6 | 7 | | 3:48.70 | |
| 29 | 5 | 1 | | 3:49.17 | |
| 30 | 6 | 0 | | 3:49.38 | |
| 31 | 4 | 7 | | 3:49.45 | |
| 32 | 1 | 4 | | 3:49.63 | |
| 33 | 1 | 1 | | 3:49.86 | |
| 34 | 4 | 3 | | 3:51.30 | |
| 35 | 1 | 2 | | 3:51.69 | NR |
| 36 | 4 | 9 | | 3:54.56 | |
| 37 | 5 | 9 | | 3:54.76 | |
| 38 | 3 | 3 | | 3:56.32 | NR |
| 39 | 4 | 6 | | 3:56.79 | |
| 40 | 4 | 0 | | 3:57.85 | NR |
| 41 | 4 | 8 | | 3:59.58 | |
| 42 | 3 | 0 | | 4:00.22 | |
| 43 | 3 | 2 | | 4:00.62 | |
| 44 | 4 | 1 | | 4:01.31 | |
| 45 | 3 | 6 | | 4:01.37 | |
| 46 | 3 | 4 | | 4:02.62 | |
| 47 | 3 | 5 | | 4:02.94 | |
| 48 | 3 | 8 | | 4:06.30 | |
| 49 | 2 | 6 | | 4:10.77 | |
| 50 | 3 | 7 | | 4:11.79 | |
| 51 | 2 | 4 | | 4:12.16 | |
| 52 | 3 | 1 | | 4:12.61 | NR |
| 53 | 2 | 5 | | 4:15.31 | |
| 54 | 3 | 9 | | 4:17.66 | |
| 55 | 2 | 3 | | 4:18.40 | |
| 56 | 2 | 2 | | 4:23.37 | |
| 57 | 2 | 1 | | 4:26.14 | |
| 58 | 2 | 7 | | 4:31.26 | |
| 59 | 2 | 9 | | 4:37.41 | |
| 60 | 2 | 0 | | 4:37.59 | |
| 61 | 2 | 8 | | 4:46.60 | |
| 1 | 3 | | | |
| 1 | 5 | | | |
| 1 | 6 | | | |
| 5 | 8 | | | |
| 7 | 1 | | | |
| 7 | 4 | | 3:40.89 | |
Final
The final was held at 19:55.
| Rank | Lane | Name | Nationality | Time | Notes |
| 6 | Paul Biedermann | GER | 3:39.15 | |
| 1 | Hao Yun | CHN | 3:39.48 | |
| 2 | Matthew Stanley | NZL | 3:41.01 | |
| 4 | 5 | Michael Klueh | USA | 3:41.29 | |
| 5 | 8 | Pál Joensen | FRO | 3:42.23 | |
| 6 | 3 | Ahmed Mathlouthi | TUN | 3:42.48 | |
| 7 | 7 | Anders Lie | DEN | 3:42.80 | |
| 4 | Mads Glæsner | DEN | 3:40.09 | |
