| Event: | Men's 800 metre freestyle |
| Competition: | 2011 World Aquatics Championships |
| Dates: | July 26, 2011 (heats) July 27, 2011 (final) |
| Competitors: | 51 |
| Nations: | 43 |
| Win Value: | 7:38.57 |
| Gold: | Sun Yang |
| Goldnoc: | CHN |
| Silver: | Ryan Cochrane |
| Silvernoc: | CAN |
| Bronze: | Gergő Kis |
| Bronzenoc: | HUN |
| Prev: | 2009 |
| Next: | 2013 |
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.
Prior to the competition, the existing world and championship records were as follows.
51 swimmers participated in 7 heats.[1]
| Rank | Heat | Lane | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|---|
| 1 | 7 | 4 | 7:45.29 | Q | |||
| 2 | 5 | 3 | 7:45.55 | Q, NR | |||
| 3 | 5 | 4 | 7:45.57 | Q | |||
| 4 | 6 | 3 | 7:48.33 | Q, NR | |||
| 5 | 6 | 7 | 7:48.86 | Q | |||
| 6 | 7 | 6 | 7:49.13 | Q | |||
| 7 | 6 | 4 | 7:49.43 | Q | |||
| 8 | 5 | 5 | 7:49.94 | Q | |||
| 9 | 6 | 5 | 7:51.59 | ||||
| 10 | 7 | 3 | 7:52.63 | ||||
| 11 | 6 | 2 | 7:54.57 | ||||
| 12 | 5 | 6 | 7:54.63 | ||||
| 13 | 7 | 2 | 7:56.84 | ||||
| 14 | 5 | 2 | 7:57.13 | ||||
| 15 | 7 | 5 | 7:58.20 | ||||
| 16 | 6 | 8 | 7:59.06 | NR | |||
| 17 | 6 | 6 | 8:01.10 | ||||
| 18 | 7 | 7 | 8:01.79 | ||||
| 19 | 4 | 6 | 8:02.07 | ||||
| 20 | 5 | 1 | 8:02.45 | ||||
| 21 | 7 | 8 | 8:03.87 | ||||
| 22 | 4 | 4 | 8:05.66 | ||||
| 23 | 3 | 2 | 8:05.98 | NR | |||
| 24 | 4 | 3 | 8:06.04 | ||||
| 25 | 5 | 7 | 8:06.14 | ||||
| 26 | 2 | 7 | 8:07.78 | ||||
| 27 | 6 | 1 | 8:08.54 | ||||
| 28 | 7 | 1 | 8:08.78 | ||||
| 29 | 4 | 7 | 8:10.35 | ||||
| 30 | 4 | 2 | 8:10.82 | ||||
| 31 | 4 | 8 | 8:11.94 | ||||
| 32 | 3 | 5 | 8:12.16 | ||||
| 33 | 4 | 5 | 8:12.90 | ||||
| 34 | 5 | 8 | 8:13.06 | ||||
| 35 | 3 | 4 | 8:13.07 | ||||
| 36 | 3 | 1 | 8:14.45 | NR | |||
| 37 | 3 | 6 | 8:17.02 | ||||
| 38 | 3 | 3 | 8:17.22 | ||||
| 39 | 2 | 6 | 8:17.83 | ||||
| 40 | 2 | 2 | 8:18.79 | NR | |||
| 41 | 4 | 1 | 8:20.41 | ||||
| 42 | 3 | 7 | 8:21.90 | NR | |||
| 43 | 3 | 8 | 8:23.37 | ||||
| 44 | 2 | 8 | 8:23.53 | ||||
| 45 | 2 | 5 | 8:27.35 | ||||
| 46 | 2 | 3 | 8:27.39 | ||||
| 47 | 2 | 1 | 8:28.07 | ||||
| 48 | 2 | 4 | 8:28.67 | ||||
| 49 | 1 | 5 | 8:38.93 | ||||
| 50 | 1 | 4 | 8:44.06 | ||||
| 51 | 1 | 3 | 9:00.87 |
The final was held at 18:41.[2]
| Rank | Lane | Name | Nationality | Time | Notes | |
|---|---|---|---|---|---|---|
| 4 | 7:38.57 | |||||
| 3 | 7:41.86 | AR, NR | ||||
| 6 | 7:44.94 | NR | ||||
| 4 | 2 | 7:45.99 | ||||
| 5 | 5 | 7:46.51 | ||||
| 6 | 8 | 7:46.52 | ||||
| 7 | 7 | 7:46.64 | ||||
| 8 | 1 | 7:55.91 |