EVENT 101 Open/Male 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 1 | Daniil OBUHOV | 13 | Braunstone | 6:34.97 |
| 2 | 3 | Oliver DORAN | 13 | Leic Peng | 6:26.12 |
| 3 | 5 | Samuel HICKS | 11 | Hinckley | 6:03.06 |
| 4 | 7 | Andrei OBUHOV | 11 | Braunstone | 6:01.70 |
| 5 | 6 | Harvey GOODWIN | 11 | Hinckley | 6:01.92 |
| 6 | 4 | Austin GRAHAM | 12 | Leic Peng | 6:03.77 |
| 7 | 2 | Nicholas LUNN | 12 | Coalville | 6:26.71 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 9 | Finley FOWLER | 10 | Coalville | 5:38.77 |
| 2 | 11 | William BURDOCK | 09 | Melton M'bry | 5:36.37 |
| 3 | 13 | Victor BRAMLEY-HOWELL | 10 | Leic Peng | 5:30.63 |
| 4 | 16 | Mason TRAYNOR | 13 | Coalville | 5:21.04 |
| 5 | 15 | Benjamin BOULTER | 08 | Leicester Ne | 5:21.87 |
| 6 | 12 | Theo BLACK | 10 | Leic Sharks | 5:30.66 |
| 7 | 10 | James GOODWIN | 05 | OadbyWigston | 5:37.20 |
| 8 | 8 | Seth GARDNER | 11 | Loughborough | 5:54.28 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 18 | Peter NIGHTINGALE | 10 | Coalville | 5:17.90 |
| 2 | 20 | Maxwell BURDETT | 12 | Leic Peng | 5:14.39 |
| 3 | 22 | Oliver LOND | 08 | Hinckley | 5:13.61 |
| 4 | 24 | Emerson-Blu GUPWELL | 10 | Braunstone | 5:11.08 |
| 5 | 23 | Ethan SIMMONDS | 09 | Leicester Ne | 5:11.64 |
| 6 | 21 | Charlie JAMES | 06 | Market Har | 5:14.27 |
| 7 | 19 | James NIGHTINGALE | 10 | Coalville | 5:14.69 |
| 8 | 17 | James HOCKEY | 09 | Coalville | 5:20.38 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 26 | Freddie BURDETT | 10 | Leic Peng | 5:03.81 |
| 2 | 28 | Lewis FITCH | 07 | Braunstone | 4:56.70 |
| 3 | 30 | Jack GOLDFINCH | 06 | Loughborough | 4:55.72 |
| 4 | 32 | James LAKE | 07 | Loughborough | 4:41.51 |
| 5 | 31 | Jack SMITH | 10 | Leic Sharks | 4:45.74 |
| 6 | 29 | Harry LUCAS | 10 | Braunstone | 4:56.46 |
| 7 | 27 | Harrison BYWATER | 07 | Loughborough | 5:03.37 |
| 8 | 25 | Jacson CRABB | 11 | Leic Sharks | 5:06.44 |