Swimming at the 2011 World Aquatics Championships – Men's 800 metre freestyle
The men's 800 metre freestyle competition of the swimming events at the 2011 World Aquatics Championships was held on July 26 with the heats and July 27 with the final.
Records
Prior to the competition, the existing world and championship records were as follows.| Name | Nation | Time | Location | Date | |
| World record Championship record | Zhang Lin | 7:32.12 | Rome | July 29, 2009 |
Results
Heats
51 swimmers participated in 7 heats.| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 7 | 4 | Sun Yang | 7:45.29 | Q | |
| 2 | 5 | 3 | Pál Joensen | 7:45.55 | Q, NR | |
| 3 | 5 | 4 | Ryan Cochrane | 7:45.57 | Q | |
| 4 | 6 | 3 | Gergő Kis | 7:48.33 | Q, NR | |
| 5 | 6 | 7 | Oussama Mellouli | 7:48.86 | Q | |
| 6 | 7 | 6 | Peter Vanderkaay | 7:49.13 | Q | |
| 7 | 6 | 4 | Sébastien Rouault | 7:49.43 | Q | |
| 8 | 5 | 5 | Chad La Tourette | 7:49.94 | Q | |
| 9 | 6 | 5 | Samuel Pizzetti | 7:51.59 | ||
| 10 | 7 | 3 | Job Kienhuis | 7:52.63 | ||
| 11 | 6 | 2 | Mads Glæsner | 7:54.57 | ||
| 12 | 5 | 6 | Dai Jun | 7:54.63 | ||
| 13 | 7 | 2 | Ryan Napoleon | 7:56.84 | ||
| 14 | 5 | 2 | Yohsuke Miyamoto | 7:57.13 | ||
| 15 | 7 | 5 | Christian Kubusch | 7:58.20 | ||
| 16 | 6 | 8 | Juan Martin Pereyra | 7:59.06 | NR | |
| 17 | 6 | 6 | Federico Colbertaldo | 8:01.10 | ||
| 18 | 7 | 7 | Heerden Herman | 8:01.79 | ||
| 19 | 4 | 6 | Anton Goncharov | 8:02.07 | ||
| 20 | 5 | 1 | Mark Randall | 8:02.45 | ||
| 21 | 7 | 8 | Sergiy Frolov | 8:03.87 | ||
| 22 | 4 | 4 | David Brandl | 8:05.66 | ||
| 23 | 3 | 2 | Mateo de Angulo | 8:05.98 | NR | |
| 24 | 4 | 3 | Uladzimir Zhyharau | 8:06.04 | ||
| 25 | 5 | 7 | Gergely Gyurta | 8:06.14 | ||
| 26 | 2 | 7 | Jan Karel Petric | 8:07.78 | ||
| 27 | 6 | 1 | Evgeny Kulikov | 8:08.54 | ||
| 28 | 7 | 1 | Nikolay Bulakhov | 8:08.78 | ||
| 29 | 4 | 7 | Mohamed Farhoud | 8:10.35 | ||
| 30 | 4 | 2 | Daniel Delgadillo Faisal | 8:10.82 | ||
| 31 | 4 | 8 | Jang Sang-Jin | 8:11.94 | ||
| 32 | 3 | 5 | Ricardo Monasterio | 8:12.16 | ||
| 33 | 4 | 5 | Florian Janistyn | 8:12.90 | ||
| 34 | 5 | 8 | Dylan Dunlop-Barrett | 8:13.06 | ||
| 35 | 3 | 4 | Ventsislav Aydarski | 8:13.07 | ||
| 36 | 3 | 1 | Stefan Sorak | 8:14.45 | NR | |
| 37 | 3 | 6 | Christian Bayo | 8:17.02 | ||
| 38 | 3 | 3 | Esteban Enderica | 8:17.22 | ||
| 39 | 2 | 6 | Anton Sveinn McKee | 8:17.83 | ||
| 40 | 2 | 2 | Kevin Soow Choy Yeap | 8:18.79 | NR | |
| 41 | 4 | 1 | Květoslav Svoboda | 8:20.41 | ||
| 42 | 3 | 7 | Ullalmath Gagan | 8:21.90 | NR | |
| 43 | 3 | 8 | Nezir Karap | 8:23.37 | ||
| 44 | 2 | 8 | Erazmo Maršanić | 8:23.53 | ||
| 45 | 2 | 5 | Sobitjon Amilov | 8:27.35 | ||
| 46 | 2 | 3 | Marko Blazevski | 8:27.39 | ||
| 47 | 2 | 1 | Pavol Jelenak | 8:28.07 | ||
| 48 | 2 | 4 | Zhen Ren Teo | 8:28.67 | ||
| 49 | 1 | 5 | Iacovos Hadjiconstantinou | 8:38.93 | ||
| 50 | 1 | 4 | Pavel Naroshkin | 8:44.06 | ||
| 51 | 1 | 3 | Heimanu Sichan | 9:00.87 |
Final
The final was held at 18:41.| Rank | Lane | Name | Nationality | Time | Notes |
| 4 | Sun Yang | 7:38.57 | |||
| 3 | Ryan Cochrane | 7:41.86 | AR, NR | ||
| 6 | Gergő Kis | 7:44.94 | NR | ||
| 4 | 2 | Oussama Mellouli | 7:45.99 | ||
| 5 | 5 | Pál Joensen | 7:46.51 | ||
| 6 | 8 | Chad La Tourette | 7:46.52 | ||
| 7 | 7 | Peter Vanderkaay | 7:46.64 | ||
| 8 | 1 | Sébastien Rouault | 7:55.91 |