EVENT 401 Female 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 2 | Amber MUIR | 11 | Rushden | 6:43.78 |
| 2 | 4 | Georgina BEEBY | 14 | Kettering | 6:33.90 |
| 3 | 6 | Evie BRAMFORD | 14 | Hinckley | 6:10.00 |
| 4 | 8 | Sophie BRUTNALL | 14 | Market Har | 6:02.56 |
| 5 | 7 | Nika BUHHAROVA | 15 | Corby | 6:08.62 |
| 6 | 5 | Sophie SHARPE | 15 | Melton M'bry | 6:13.90 |
| 7 | 3 | Millie DAY | 17 | Rushden | 6:39.65 |
| 8 | 1 | Kaylyn PRIOR | 11 | Corby | 7:47.49 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 10 | Aaliyah BEETSON | 16 | Wellingboro | 5:57.43 |
| 2 | 12 | Beth REBHAN | 13 | Corby | 5:43.11 |
| 3 | 14 | Eva GALLAGHER | 16 | Corby | 5:38.27 |
| 4 | 16 | Alice BALL | 28 | Market Har | 5:20.00 |
| 5 | 15 | Elisa GIRAUD | 13 | Corby | 5:32.26 |
| 6 | 13 | Isabelle PAWLOWSKI | 13 | Corby | 5:41.10 |
| 7 | 11 | Georgia PARKER | 14 | Corby | 5:56.30 |
| 8 | 9 | Harriet JENNINGS | 12 | Market Har | 6:00.11 |