EVENT 1 Boy Open 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 2 | 1 | Luca SLOAN | 13 | Weymouth | 7:26.09 |
| 3 | 2 | Kit FREEMAN | 11 | Blandford | 6:44.55 |
| 4 | 3 | Jenson LOWE | 12 | Poole | 6:14.23 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 4 | Toby SIMS | 13 | Seagulls SC | 6:12.32 |
| 2 | 5 | Gethin WILSON | 10 | Poole | 6:04.23 |
| 3 | 6 | Alfie CRANE | 10 | Seagulls SC | 5:46.82 |
| 4 | 7 | Oliver COE | 12 | Poole | 5:38.57 |
| 5 | 8 | Finlay LAWS | 10 | S Bournem'th | 5:34.03 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 10 | Miron WOZNIAK | 09 | Blandford | 5:23.50 |
| 2 | 12 | Matthew PROWSE | 08 | West Dorset | 5:18.73 |
| 3 | 14 | Toby LACEY | 08 | S Bournem'th | 4:47.36 |
| 4 | 13 | Thomas DEWEY | 08 | Seagulls SC | 4:48.62 |
| 5 | 11 | Connor PITTWOOD | 10 | Poole | 5:20.24 |
| 6 | 9 | George DEFRIES | 09 | Seagulls SC | 5:29.94 |