EVENT 401 Open/Male 09 /Over 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 1 | Cyril BAO | 10 | Grantham | |
| 2 | 2 | Henry DOLAN | 13 | Grantham | |
| 3 | 3 | George DOLAN | 10 | Grantham | |
| 4 | 4 | Benjamin SHEARN | 12 | Grantham | |
| 5 | 5 | Henry LEONARD | 10 | Grantham | 7:13.24 |
| 6 | 6 | William PENNOCK | 12 | Grantham | 6:25.28 |
| 7 | 7 | Freddie HIRST | 12 | Grantham | 6:09.65 |
| 8 | 8 | Elliot GLEAVE | 13 | Grantham | 6:04.46 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 9 | Louis WRIGHT | 13 | Grantham | 5:54.26 |
| 2 | 10 | Derrin BROCKLEBANK | 12 | Grantham | 5:27.14 |
| 3 | 11 | Jimmin BAO | 13 | Grantham | 5:22.52 |
| 4 | 12 | Arthur BREARLEY-NEWSOM | 15 | Grantham | 5:21.97 |
| 5 | 13 | Toby EDMONDSON | 12 | Grantham | 5:19.71 |
| 6 | 14 | Yu Ching (Eugene) CHEU | 15 | Grantham | 5:13.04 |
| 7 | 15 | Thomas HILLSON | 13 | Grantham | 5:05.51 |
| 8 | 16 | George LEONARD | 14 | Grantham | 5:02.63 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 18 | Leo BARNETT | 14 | Grantham | 4:59.35 |
| 2 | 20 | Francesco MONACO | 14 | Grantham | 4:40.12 |
| 3 | 22 | Ben CARLYLE | 16 | Grantham | 4:18.45 |
| 4 | 24 | Zach HOPKINSON | 17 | Grantham | 4:17.21 |
| 5 | 23 | James DOBNEY | 22 | Grantham | 4:18.00 |
| 6 | 21 | Kieran LUCY | 16 | Grantham | 4:33.73 |
| 7 | 19 | Markas PARAPIJONAVICIU | 13 | Grantham | 4:57.13 |
| 8 | 17 | Joshua KIM | 14 | Grantham | 5:01.11 |