EVENT 301 Womens Open 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 2 | 1 | Anastasia WILKINSON | 14 | Hatfield | 5:19.79 |
| 3 | 3 | Olivia NEWMAN-BARONIUS | 13 | Putteridge | 5:19.32 |
| 4 | 5 | Eloise BAILEY | 17 | Modernian | 5:18.26 |
| 5 | 4 | Gracie TROTTER | 16 | C Beds SS | 5:18.91 |
| 6 | 2 | Lily BEMMER | 16 | Deben | 5:19.50 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 7 | Rebecca MERRILL | 18 | Co Cambridge | 5:17.56 |
| 2 | 9 | Leah WIGHTMAN | 14 | West Norfolk | 5:17.30 |
| 3 | 11 | Tilly ANEMA | 18 | Co Norwich | 5:16.31 |
| 4 | 13 | Holly LAMB | 14 | Basildon Ph | 5:11.83 |
| 5 | 12 | Ciara WOOKEY | 15 | Colchester | 5:12.59 |
| 6 | 10 | Kiera BLUNDEN | 14 | Chelmsford | 5:16.83 |
| 7 | 8 | Molly MONK | 15 | Dereham | 5:17.30 |
| 8 | 6 | Daisy HILL | 20 | Co Norwich | 5:18.26 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 15 | Matilda RANSOME | 13 | Co Cambridge | 5:09.60 |
| 2 | 17 | Ellie O'KEEFFE | 19 | Co Cambridge | 5:08.57 |
| 3 | 19 | May BRADBURN | 15 | Chelmsford | 5:05.37 |
| 4 | 21 | Lily MERRETT | 16 | Co St Albans | 5:04.93 |
| 5 | 20 | Zara KEEGAN | 17 | Co Cambridge | 5:05.22 |
| 6 | 18 | Charlotte NORMAN | 14 | teamipswich | 5:07.70 |
| 7 | 16 | Almudena VISSER VELEZ | 17 | Co Cambridge | 5:09.28 |
| 8 | 14 | Olivia LEE | 15 | Co Peterboro | 5:10.74 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 23 | Harriet SALISBURY | 15 | Co Peterboro | 5:02.80 |
| 2 | 25 | Lucie PECK | 16 | St Felix Sch | 5:00.63 |
| 3 | 27 | Ruby WHEELER | 13 | Basildon Ph | 4:58.90 |
| 4 | 29 | Amelia MONAGHAN | 17 | Co Peterboro | 4:45.03 |
| 5 | 28 | Ellie WHEELER | 17 | Basildon Ph | 4:55.37 |
| 6 | 26 | Celyn WALMSLEY | 18 | Team Luton | 4:59.05 |
| 7 | 24 | Natalie SANFORD | 15 | St Felix Sch | 5:01.30 |
| 8 | 22 | Charlotte WHITE | 14 | West Suffolk | 5:04.00 |