| Heat Number - 1 | |||||
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 2 | 5 | Jago Derrington | 13 | Bishop Stort | 5:01.89 |
| 3 | 1 | Ethan Howard | 12 | Potters Bar | 5:12.94 |
| 4 | 3 | Nathanial Mapley | 13 | Co St Albans | 5:03.81 |
| 5 | 2 | Ryan Wall | 12 | Royston | 5:05.35 |
| 6 | 4 | Cub Maddison | 13 | Hatfield | 5:03.32 |
| Heat Number - 2 | |||||
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 2 | 6 | Lucas Hartley | 12 | Hatfield | 5:00.79 |
| 3 | 8 | Samuel Pyefinch | 14 | Tring | 4:35.81 |
| 4 | 10 | Peter Soczewka | 14 | Hatfield | 4:27.83 |
| 5 | 9 | Ahaan Saini | 15 | Hatfield | 4:27.86 |
| 6 | 7 | Henry Newbury-Kemp | 14 | Hemel Hemp | 4:44.84 |