EVENT 509 Women Open 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 2 | Evangeline Pierce | 14 | | Basildon Ph | 4:44.41 |
| 2 | 4 | Molly Redgrave | 17 | | Colchester | 4:42.74 |
| 3 | 6 | Cathryn Thomson | 31 | | St Ives | 4:42.50 |
| 4 | 8 | Charlotte Tree | 17 | | Colchester | 4:40.70 |
| 5 | 7 | Indy Scott | 16 | | Co Cambridge | 4:40.90 |
| 6 | 5 | Sophie Dowding | 14 | | teamipswich | 4:42.60 |
| 7 | 3 | Charlotte Williams | 15 | | Hatfield | 4:43.70 |
| 8 | 1 | Abigail Wickens | 14 | S8 | Flitwick | 6:31.49 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 10 | Antonia Jubb | 16 | | Hatfield | 4:40.07 |
| 2 | 12 | Gracie Comitti | 14 | | Basildon Ph | 4:38.44 |
| 3 | 14 | Yoshi Eschen | 21 | | Co Cambridge | 4:37.66 |
| 4 | 16 | Lucy Young | 16 | | Modernian | 4:35.38 |
| 5 | 15 | Cait Cotter | 14 | | Chelmsford | 4:36.09 |
| 6 | 13 | Alexa Mann | 15 | | Chelmsford | 4:37.74 |
| 7 | 11 | Summer Kennedy | 20 | | Co Norwich | 4:39.88 |
| 8 | 9 | Gabriela Gomez Pavon | 14 | | Potters Bar | 4:40.18 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 18 | Erin Wilkinson | 16 | | Basildon Ph | 4:34.79 |
| 2 | 20 | Charlotte Norman | 16 | | teamipswich | 4:32.00 |
| 3 | 22 | Jessica-Jane Applegate | 25 | S14 | Co Norwich | 4:24.70 |
| 4 | 24 | Harriet Salisbury | 17 | | Co Peterboro | 4:20.88 |
| 5 | 23 | Ruby Wheeler | 15 | | Basildon Ph | 4:21.30 |
| 6 | 21 | Tia Gardiner | 19 | | Basildon Ph | 4:31.20 |
| 7 | 19 | Madelyn Latimer-Hicks | 17 | | St Felix Sch | 4:33.35 |
| 8 | 17 | Francesca Baber | 15 | | Flitwick | 4:35.37 |