EVENT 102 Female 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 3 | 1 | Isabelle WATSON | 10 | Dunstable | |
| 4 | 3 | Carolina PRUSAK | 12 | Team Luton | 6:43.40 |
| 5 | 2 | Sara WAGAN | 9 | Putteridge | 7:06.40 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 4 | Ruth BISCOE | 11 | Team Luton | 6:03.80 |
| 2 | 6 | Cora PAYNE | 11 | Dunstable | 5:51.09 |
| 3 | 8 | Lillian OWENS | 11 | Putteridge | 5:43.56 |
| 4 | 10 | Thea SLATER | 13 | Team Luton | 5:41.79 |
| 5 | 9 | Alyssia LAKE | 14 | Linslade | 5:41.81 |
| 6 | 7 | Lucy BISCOE | 10 | Team Luton | 5:49.20 |
| 7 | 5 | Mary BATTERSBY | 12 | Team Luton | 6:01.30 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 12 | Madison BROWN | 16 | Bletchley | 5:32.28 |
| 2 | 15 | Elissa NEO | 12 | Linslade | 5:17.56 |
| 3 | 17 | Olivia PIASKOWSKA | 13 | Dunstable | 5:13.50 |
| 4 | 19 | Abigail PERRY | 14 | Dunstable | 5:01.78 |
| 5 | 18 | Libby FLITTON | 12 | Dunstable | 5:09.30 |
| 6 | 16 | Tilly HOWELLS | 12 | Verulam | 5:17.45 |
| 7 | 14 | Darcie CADER | 13 | Berkhamsted | 5:30.04 |
| 8 | 11 | Molly SMITH | 14 | West Suffolk | 5:35.82 |