EVENT 301 Female 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 3 | 1 | Milly Webb | 10 | Northampton | 7:30.00 |
| 4 | 3 | Evie Littlefield | 12 | Shrewsbury | 6:45.09 |
| 5 | 2 | Isabella Knight | 14 | Northampton | 7:00.00 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 5 | Ellie Poulton-Burbank | 13 | Co Leicester | 6:30.00 |
| 2 | 7 | Jessica Greenhalgh | 13 | Co Leicester | 6:22.65 |
| 3 | 9 | Myla Dizon | 13 | Co Leicester | 6:10.00 |
| 4 | 11 | Ava Steans | 14 | Co Leicester | 6:00.82 |
| 5 | 10 | Philippa Bodey | 13 | Co Leicester | 6:07.40 |
| 6 | 8 | Sophie Lane | 12 | Co Leicester | 6:12.65 |
| 7 | 6 | Amy Edwards | 13 | Boldmere | 6:24.89 |
| 8 | 4 | Brooke Bartley | 12 | Cheadle | 6:31.39 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 13 | Sofia Reedha | 13 | Co Leicester | 5:54.40 |
| 2 | 15 | Abigail Golynker | 14 | Co Leicester | 5:50.61 |
| 3 | 17 | Emily Denton | 15 | Northampton | 5:42.30 |
| 4 | 19 | Chiara Reedha | 15 | Co Leicester | 5:30.58 |
| 5 | 18 | Chloe Gent | 14 | Co Leicester | 5:38.25 |
| 6 | 16 | Marta Uciecha | 14 | Co Leicester | 5:50.00 |
| 7 | 14 | I Parsons-Loades | 13 | Repton | 5:53.60 |
| 8 | 12 | Millie Cadden | 17 | Long Eaton | 5:57.16 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 21 | Jessica Lines | 15 | Co Leicester | 5:24.09 |
| 2 | 23 | Jessica Oxley | 15 | Co Leicester | 5:18.60 |
| 3 | 25 | Francesca Harrison | 15 | Co Leicester | 5:11.30 |
| 4 | 27 | Janie Finch | 14 | Co Leicester | 5:06.22 |
| 5 | 26 | Alice Streeter | 18 | Co Leicester | 5:07.57 |
| 6 | 24 | Kate Andrews | 16 | Co Leicester | 5:17.11 |
| 7 | 22 | Holly Gent | 13 | Co Leicester | 5:23.30 |
| 8 | 20 | Sophie Statham-Gill | 15 | Co Leicester | 5:29.23 |