EVENT 223 Female 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 3 | 1 | Charlotte Ryan | 25 | S6 | Runnymede | 8:45.70 |
| 4 | 3 | Lily Herring | 17 | S10 | Co Norwich | 5:40.38 |
| 5 | 2 | Ida Corcoran | 16 | S9 | Flitwick | 5:56.43 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 4 | Abigail Wickens | 18 | S8 | Flitwick | 5:37.60 |
| 2 | 6 | Elizabeth Pert | 15 | | Norwich Swan | 4:48.50 |
| 3 | 8 | Milly Johnson | 15 | | West Norfolk | 4:46.90 |
| 4 | 10 | Isabella Savage | 16 | | Potters Bar | 4:46.31 |
| 5 | 9 | Olivia Palmer | 15 | | Co Norwich | 4:46.67 |
| 6 | 7 | Anastasja Wall | 15 | | Co Norwich | 4:48.20 |
| 7 | 5 | Grace Mutton | 15 | | Deben | 4:48.83 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 12 | Cassandra Pereira | 15 | | Watford SC | 4:45.93 |
| 2 | 14 | Elena Buckley | 15 | | Basildon Ph | 4:45.03 |
| 3 | 16 | Esmie Kidman | 19 | | West Norfolk | 4:43.34 |
| 4 | 18 | Ava Black | 18 | | Co St Albans | 4:42.71 |
| 5 | 17 | Aislin Foley-Wright | 18 | | Basildon Ph | 4:42.96 |
| 6 | 15 | Ava Turner | 16 | | Basildon Ph | 4:44.62 |
| 7 | 13 | Daisy Jubb | 15 | | Co St Albans | 4:45.31 |
| 8 | 11 | Emma Cushion | 15 | | Co Peterboro | 4:46.15 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 20 | Antonia Elias | 16 | | Hatfield | 4:41.90 |
| 2 | 22 | Isabel Thomas | 17 | | Newmarket | 4:40.62 |
| 3 | 24 | Eleanor McLeod | 17 | | Putteridge | 4:39.42 |
| 4 | 26 | Lexie Goodman | 18 | | Basildon Ph | 4:38.90 |
| 5 | 25 | E Barth-Wehrenalp | 15 | | Chelmsford | 4:39.30 |
| 6 | 23 | Francesca Barber | 16 | | Co Norwich | 4:39.81 |
| 7 | 21 | Summer Evason | 16 | | Watford SC | 4:40.80 |
| 8 | 19 | Ella Deaton | 16 | | Newmarket | 4:42.69 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 28 | Amelia Porzio | 17 | | Putteridge | 4:36.46 |
| 2 | 30 | Lois Smith | 15 | | Basildon Ph | 4:35.65 |
| 3 | 32 | Jessica-Jane Applegate | 29 | S14 | Co Norwich | 4:34.50 |
| 4 | 34 | Ruby Chapman | 19 | | Norwich Swan | 4:33.97 |
| 5 | 33 | Erin Uttridge | 16 | | teamipswich | 4:34.26 |
| 6 | 31 | Valentina Tinnirello | 15 | | Potters Bar | 4:35.60 |
| 7 | 29 | Amelia Saunders | 17 | | Norwich Swan | 4:36.14 |
| 8 | 27 | Genevieve White | 17 | | Co Cambridge | 4:36.70 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 36 | Gabriella Troman | 16 | | teamipswich | 4:33.56 |
| 2 | 38 | Millie Richardson | 19 | | Hatfield | 4:32.49 |
| 3 | 40 | Sadie Hunter | 17 | | Co Peterboro | 4:28.50 |
| 4 | 42 | Chloe Barnard | 16 | | Basildon Ph | 4:28.22 |
| 5 | 41 | Cailin Hehir | 17 | | Watford SC | 4:28.32 |
| 6 | 39 | Anabelle Kett | 16 | | Co Peterboro | 4:32.04 |
| 7 | 37 | Erin Younger | 18 | | Co St Albans | 4:32.76 |
| 8 | 35 | Ella Dawson | 17 | | Chelmsford | 4:33.74 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 44 | Annie McLeod | 17 | | Putteridge | 4:24.92 |
| 2 | 46 | Rebecca Coogan | 17 | | Thurrock | 4:24.70 |
| 3 | 48 | Ever Ives | 16 | | Hatfield | 4:23.64 |
| 4 | 50 | Cait Cotter | 18 | | Chelmsford | 4:15.00 |
| 5 | 49 | Jasmine Hall | 15 | | Basildon Ph | 4:16.94 |
| 6 | 47 | Amelia Fenner | 15 | | Basildon Ph | 4:23.72 |
| 7 | 45 | Sophie Dowding | 18 | | teamipswich | 4:24.75 |
| 8 | 43 | Alexa Mann | 19 | | DunmowAtlant | 4:26.70 |