EVENT 601 Open/Male 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 3 | 1 | Kieran Ng | 14 | Co Peterboro | 5:04.50 |
| 4 | 3 | Harvey Isle | 19 | West Norfolk | 5:03.71 |
| 5 | 2 | Thomas Spelman | 17 | Stowmarket | 5:03.79 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 5 | Theodore Monk | 16 | Co Cambridge | 5:02.21 |
| 3 | 7 | Patryk Nowak | 14 | Co Peterboro | 5:01.25 |
| 4 | 9 | Danylo Kravchenko | 15 | New Hall | 4:57.25 |
| 5 | 8 | Ashton Blake | 15 | Basildon Ph | 5:00.89 |
| 6 | 6 | Csanad Rehus | 15 | Co Peterboro | 5:01.69 |
| 7 | 4 | Joshua Jones | 15 | West Norfolk | 5:02.52 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 11 | Daniel Thompson | 17 | Thurrock | 4:56.98 |
| 2 | 13 | Oliver Fuller | 14 | Co Cambridge | 4:54.91 |
| 3 | 15 | Daniel De Filippo | 15 | Flitwick | 4:53.50 |
| 4 | 17 | Frank Lamb | 15 | Co Peterboro | 4:49.20 |
| 5 | 16 | George Prince | 16 | Putteridge | 4:51.30 |
| 6 | 14 | Jacob Bacon | 14 | Co Peterboro | 4:53.90 |
| 7 | 12 | Daniel Meier | 17 | Biggleswade | 4:55.41 |
| 8 | 10 | Benjamin Taggart | 17 | Watford SC | 4:57.08 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 19 | Edward Ormsby | 17 | Co Cambridge | 4:44.40 |
| 2 | 21 | Oscar Winterburn | 16 | teamipswich | 4:41.43 |
| 3 | 23 | Harrison Shaw | 17 | Flitwick | 4:37.10 |
| 4 | 25 | Patch Robinson | 17 | teamipswich | 4:32.50 |
| 5 | 24 | Daniel McGuinness | 18 | Basildon Ph | 4:35.90 |
| 6 | 22 | Reece Burns | 16 | Chelmsford | 4:38.60 |
| 7 | 20 | Samuel Jeffrey | 17 | Hatfield | 4:43.64 |
| 8 | 18 | Kian Lee | 16 | Co Peterboro | 4:48.35 |