Swimming at the 2003 World Aquatics Championships – Men's 800 metre freestyle
# Swimming at the 2003 World Aquatics Championships – Men's 800 metre freestyle

The Men's 800 Freestyle event at the 10th FINA World Aquatics Championships swam on July 24–25, 2003 in Barcelona, Spain. Preliminary heats of the event were swum during the morning session on July 24, with the Final being held during the evening session on July 25.

Prior to the start of the event, the existing World (WR) and Championship (CR) records were both:

## Results

### Final

| Place | Swimmer | Nation | Time | Notes |
| - | - | - | - | - |
| 1 | Grant Hackett | Australia | 7:43.82 | |
| 2 | Larsen Jensen | USA | 7:48.09 | NR |
| 3 | Ihor Chervynskyi | Ukraine | 7:53.15 | |
| 4 | Graeme Smith | Great Britain | 7:53.48 | |
| 5 | Dragoș Coman | Romania | 7:57.22 | |
| 6 | Kurtis MacGillivary | Canada | 8:01.75 | |
| 7 | Shunichi Fujita | Japan | 8:02.38 | |
| 8 | Lin Zhang | China | 8:04.10 | |

### Preliminaries

| Rank | Heat+Lane | Swimmer | Nation | Time | Notes |
| - | - | - | - | - | - |
| 1 | H4 L4 | Grant Hackett | Australia | 7:55.15 | q |
| 2 | H2 L4 | Graeme Smith | Great Britain | 7:58.66 | q |
| 3 | H3 L4 | Larsen Jensen | United States | 7:59.18 | q |
| 4 | H4 L3 | Kurtis MacGillivary | Canada | 7:59.58 | q |
| 5 | H2 L3 | Dragoș Coman | Romania | 8:00.44 | q |
| 6 | H3 L2 | Ihor Chervynskyi | Ukraine | 8:00.61 | q |
| 7 | H2 L2 | Shunichi Fujita | Japan | 8:02.84 | q |
| 8 | H3 L1 | Lin Zhang | China | 8:04.74 | q |
| 9 | H3 L5 | Stephen Penfold | Australia | 8:06.48 | |
| 10 | H3 L7 | Shilo Ayalon | Israel | 8:07.85 | |
| 11 | H2 L1 | Hannes Kalteis | Austria | 8:08.17 | |
| 12 | H4 L7 | Chad Carvin | United States | 8:08.48 | |
| 13 | H2 L6 | Dimitros Manganas | Greece | 8:10.07 | |
| 14 | H2 L7 | Felipe Araujo | Brazil | 8:10.56 | |
| 15 | H3 L6 | Kyu Chul Han | South Korea | 8:13.47 | |
| 16 | H4 L8 | Gian Carlo Zolezzi | Chile | 8:14.62 | |
| 17 | H4 L1 | Luiz Lima | Brazil | 8:15.08 | |
| 18 | H4 L2 | Cheng Yu | China | 8:16.23 | |
| 19 | H3 L3 | Rick Say | Canada | 8:17.31 | |
| 20 | H3 L8 | Yi-Khy Saw | Malaysia | 8:22.99 | |
| 21 | H2 L8 | Shai Livant | Israel | 8:24.14 | |
| 22 | H1 L4 | Mohammad Naeem Masri | Syria | 8:30.00 | |
| 23 | H1 L3 | Kwok Leung Chung | Hong Kong | 8:31.10 | |
| 24 | H1 L5 | Roberto Peñailillo | Chile | 8:34.10 | |
| 25 | H1 L6 | Neils Agius | Malta | 9:09.73 | |
| 26 | H1 L2 | Steven Mangroo | Seychelles | 9:16.60 | |
| 27 | H1 L7 | Barnsley Albert | Seychelles | 9:27.30 | |
| - | - | David Davies | Great Britain | DNS | |
| - | - | Emiliano Brembilla | Italy | DNS | |
| - | - | Trevor Kakunze | Burundi | DNS | |
