EVENT 401 Boys 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 1 | Barnaby DURANT | 10 | Grantham | |
| 2 | 2 | George LEONARD | 11 | Grantham | |
| 3 | 3 | Elliot GLEAVE | 10 | Grantham | |
| 4 | 5 | Joshua KIM | 11 | Grantham | |
| 5 | 6 | Oscar CHEN REES | 11 | Grantham | |
| 6 | 7 | Leo BARNETT | 11 | Grantham | 7:38.23 |
| 7 | 8 | Fabian KOLASA | 12 | Grantham | 6:37.97 |
| 8 | 9 | A BREARLEY-NEWSOME | 12 | Grantham | 6:29.90 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 11 | Theo BACON | 13 | Grantham | 6:01.90 |
| 2 | 14 | Daniel DEGNAN | 15 | Grantham | 4:58.32 |
| 3 | 16 | Zach HOPKINSON | 14 | Grantham | 4:34.16 |
| 4 | 18 | Owen HATHWAY | 17 | Grantham | 4:17.40 |
| 5 | 17 | Joshua CLARKE | 15 | Grantham | 4:28.38 |
| 6 | 15 | Jacob FISH | 14 | Grantham | 4:42.73 |
| 7 | 12 | Oscar DURANT | 12 | Grantham | 5:50.95 |
| 8 | 10 | Ben CARLYLE | 13 | Grantham | 6:03.00 |