EVENT 509 Womens Open 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club/Country | Time |
| 1 | 1 | Helen THOMPSON | 16 | S14 | Colchester | 7:14.99 |
| 2 | 3 | Jemima WAYMAN | 16 | | Deben | 4:39.47 |
| 3 | 5 | Lauren YOUNG | 16 | | Flitwick | 4:38.95 |
| 4 | 7 | Ruby GREENHALF | 14 | | Co Norwich | 4:37.50 |
| 5 | 6 | Ella TURNER | 14 | | Basildon Ph | 4:37.70 |
| 6 | 4 | Bianka MISIKOVA | 16 | | Hatfield | 4:39.15 |
| 7 | 2 | Ela NORTON | 15 | | Hatfield | 4:39.81 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club/Country | Time |
| 1 | 9 | Eloise BAILEY | 17 | | Modernian | 4:37.30 |
| 2 | 11 | Olivia LEE | 15 | | Co Peterboro | 4:35.60 |
| 3 | 13 | Matilda TURNER | 16 | | Bor of Brox | 4:35.22 |
| 4 | 15 | Ella HALE | 16 | | West Suffolk | 4:34.74 |
| 5 | 14 | Tess WESLEY | 15 | | Newmarket | 4:34.74 |
| 6 | 12 | Tilly ANEMA | 18 | | Co Norwich | 4:35.58 |
| 7 | 10 | Carys BREALEY | 15 | | Harlow Pen | 4:36.80 |
| 8 | 8 | Maeve POOLEY | 14 | | West Suffolk | 4:37.30 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club/Country | Time |
| 1 | 17 | Madelyn LATIMER-HICKS | 15 | | St Felix Sch | 4:33.35 |
| 2 | 19 | Abbie BARNWELL | 16 | | Team Luton | 4:31.85 |
| 3 | 21 | Billie GRANT | 17 | | Hatfield | 4:31.58 |
| 4 | 23 | Katie HAMMOND | 16 | | Co Cambridge | 4:28.08 |
| 5 | 22 | Daisy HILL | 20 | | Co Norwich | 4:30.03 |
| 6 | 20 | Matilda BOGLE | 13 | | teamipswich | 4:31.70 |
| 7 | 18 | Charlotte NORMAN | 14 | | teamipswich | 4:32.00 |
| 8 | 16 | Holly LAMB | 14 | | Basildon Ph | 4:34.66 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club/Country | Time |
| 1 | 25 | May BRADBURN | 15 | | Chelmsford | 4:26.00 |
| 2 | 27 | Rebecca HOWELL | 16 | | Basildon Ph | 4:21.82 |
| 3 | 29 | Charlotte WALKER | 17 | | St Felix Sch | 4:21.06 |
| 4 | 31 | Mackenzie WHYATT | 17 | | Co Peterboro | 4:18.30 |
| 5 | 30 | Abbie LOW | 17 | | Chelmsford | 4:20.80 |
| 6 | 28 | Ruby WHEELER | 13 | | Basildon Ph | 4:21.30 |
| 7 | 26 | Lily MERRETT | 16 | | Co St Albans | 4:25.92 |
| 8 | 24 | Harriet SALISBURY | 15 | | Co Peterboro | 4:27.10 |