EVENT 223 Female 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 3 | 2 | Ziva Barrick | 15 | S10 | Colchester P | 6:31.44 |
| 4 | 4 | Lily Herring | 16 | S10 | Norfolk Vikg | 5:36.33 |
| 5 | 3 | Ida Corcoran | 15 | S9 | Flitwick | 6:16.51 |
| 6 | 1 | Charlotte Ryan | 24 | S6 | Runnymede | 9:00.81 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 6 | Ella Deaton | 15 | | Newmarket | 4:49.32 |
| 2 | 8 | Molly Burrows | 15 | | Co Peterboro | 4:47.53 |
| 3 | 10 | Francesca Howell | 16 | | Chelmsford | 4:46.27 |
| 4 | 12 | Lily Farr | 16 | | Flitwick | 4:45.30 |
| 5 | 11 | Isabella Savage | 15 | | Potters Bar | 4:46.03 |
| 6 | 9 | Abigail Riches | 16 | | Co Norwich | 4:46.67 |
| 7 | 7 | Honor Beverstock | 15 | | Hatfield | 4:47.76 |
| 8 | 5 | Abigail Wickens | 17 | S8 | Flitwick | 5:30.70 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 14 | Miriam Moukdad | 18 | | Bishop Stort | 4:43.83 |
| 2 | 16 | Eleanor McLeod | 16 | | Putteridge | 4:42.73 |
| 3 | 18 | Lily Hayward | 16 | | Epping For't | 4:42.33 |
| 4 | 20 | Eveline Gaydon | 15 | | Colchester | 4:41.04 |
| 5 | 19 | Keira-Mae Ingram | 17 | | Co St Albans | 4:41.16 |
| 6 | 17 | Francesca Barber | 15 | | Co Norwich | 4:42.60 |
| 7 | 15 | Ava Black | 17 | | Co St Albans | 4:43.16 |
| 8 | 13 | Antonia Elias | 15 | | Hatfield | 4:44.20 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 22 | Amelia Saunders | 16 | | St Felix Sch | 4:40.20 |
| 2 | 24 | Erin Younger | 17 | | Co St Albans | 4:38.76 |
| 3 | 26 | Gabriela Gomez Pavon | 17 | | Potters Bar | 4:37.58 |
| 4 | 28 | Genevieve White | 16 | | Co Cambridge | 4:36.70 |
| 5 | 27 | Millie Richardson | 18 | | Hatfield | 4:36.80 |
| 6 | 25 | Anabelle Kett | 15 | | Co Peterboro | 4:38.30 |
| 7 | 23 | Amelia Porzio | 16 | | Putteridge | 4:38.79 |
| 8 | 21 | Amy Meyer | 15 | | Biggleswade | 4:40.50 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 30 | Ruby Chapman | 18 | | Norwich Swan | 4:35.73 |
| 2 | 32 | Lisa Leinemann | 17 | | Chelmsford | 4:35.10 |
| 3 | 34 | Erin Uttridge | 15 | | teamipswich | 4:34.26 |
| 4 | 36 | Cailin Hehir | 16 | | Watford SC | 4:33.94 |
| 5 | 35 | Gabriella Troman | 15 | | teamipswich | 4:34.26 |
| 6 | 33 | Ella Dawson | 16 | | Chelmsford | 4:34.62 |
| 7 | 31 | Abigail Crawley | 19 | | teamipswich | 4:35.14 |
| 8 | 29 | Sophie Palmer | 15 | | Basildon Ph | 4:36.23 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 38 | Lexie Goodman | 17 | | Basildon Ph | 4:32.56 |
| 2 | 40 | Grace Robinson | 15 | | St Felix Sch | 4:32.20 |
| 3 | 42 | Jessica-Jane Applegate | 28 | S14 | Co Norwich | 4:31.64 |
| 4 | 44 | Sadie Hunter | 16 | | Co Peterboro | 4:29.92 |
| 5 | 43 | Chloe Barnard | 15 | | Basildon Ph | 4:29.99 |
| 6 | 41 | Weronika Mikolajewska | 16 | | Co Peterboro | 4:31.97 |
| 7 | 39 | Ever Ives | 15 | | Hatfield | 4:32.40 |
| 8 | 37 | Adel Zakrzewski | 21 | | Co Norwich | 4:33.19 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 46 | Alexa Mann | 18 | | Chelmsford | 4:28.50 |
| 2 | 48 | Annie McLeod | 16 | | Putteridge | 4:25.86 |
| 3 | 50 | Ruby Wheeler | 18 | | Basildon Ph | 4:22.91 |
| 4 | 52 | Cait Cotter | 17 | | Chelmsford | 4:16.97 |
| 5 | 51 | Matilda Bogle | 18 | | teamipswich | 4:19.80 |
| 6 | 49 | Sophie Dowding | 17 | | teamipswich | 4:25.09 |
| 7 | 47 | Talia Staines | 22 | | Team Luton | 4:26.09 |
| 8 | 45 | Francesca Baber | 18 | | Co Cambridge | 4:28.96 |