EVENT 231 Women 15 Yrs/Over 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 2 | Isabelle Barber | 15 | Stowmarket | 4:46.85 |
| 2 | 4 | Alexa Mann | 15 | Basildon Ph | 4:45.69 |
| 3 | 6 | Charlotte Williams | 15 | Hatfield | 4:45.30 |
| 4 | 8 | Molly Redgrave | 17 | Colchester | 4:42.74 |
| 5 | 7 | Francesca Key | 16 | Thurrock | 4:43.02 |
| 6 | 5 | Menna Walmsley | 17 | Team Luton | 4:45.34 |
| 7 | 3 | Anna-Lucia Fenner | 15 | Basildon Ph | 4:46.17 |
| 8 | 1 | Romilly Marks | 15 | Newmarket | 4:47.82 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 10 | Charlotte Tree | 17 | Colchester | 4:41.11 |
| 2 | 12 | Sophie Payne | 19 | Hatfield | 4:40.38 |
| 3 | 14 | Charlotte White | 16 | West Suffolk | 4:38.46 |
| 4 | 16 | Jessica Woodward | 18 | Hatfield | 4:37.40 |
| 5 | 15 | Lauren Stott | 19 | Hatfield | 4:38.13 |
| 6 | 13 | Abbie Barnwell | 18 | Team Luton | 4:39.00 |
| 7 | 11 | Georgina Munday | 17 | Modernian | 4:40.69 |
| 8 | 9 | Francesca Baber | 15 | Flitwick | 4:41.40 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 18 | Matilda Ransome | 15 | Co Cambridge | 4:36.95 |
| 2 | 20 | Jessica Keogh | 17 | Hatfield | 4:36.20 |
| 3 | 22 | Erin Wilkinson | 16 | Basildon Ph | 4:35.31 |
| 4 | 24 | Madelyn Latimer-Hicks | 17 | St Felix Sch | 4:33.35 |
| 5 | 23 | Olivia Lee | 17 | Co Peterboro | 4:34.12 |
| 6 | 21 | Eloise Bailey | 19 | Modernian | 4:35.70 |
| 7 | 19 | Ella Turner | 16 | Basildon Ph | 4:36.50 |
| 8 | 17 | Ruby Greenhalf | 16 | Co Norwich | 4:37.36 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 26 | Katie Hammond | 18 | Co Cambridge | 4:31.59 |
| 2 | 28 | Erin O'Meara | 18 | Co St Albans | 4:27.52 |
| 3 | 30 | Shannon Stott | 21 | Hatfield | 4:22.44 |
| 4 | 32 | Harriet Salisbury | 17 | Co Peterboro | 4:20.88 |
| 5 | 31 | Ruby Wheeler | 15 | Basildon Ph | 4:21.30 |
| 6 | 29 | Ellie Wheeler | 19 | Basildon Ph | 4:22.71 |
| 7 | 27 | Holly Lamb | 16 | Basildon Ph | 4:30.10 |
| 8 | 25 | Matilda Bogle | 15 | teamipswich | 4:31.70 |