EVENT 503 Girls Open 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 1 | Alice RICHARDSON | 10 | Harpenden | 6:46.35 |
| 2 | 3 | Gemma PETERS | 10 | UEA Norwich | 6:49.28 |
| 3 | 5 | Ciara WOOKEY | 10 | Colchester | 6:43.88 |
| 4 | 7 | Libby MAGILL | 10 | Hatfield | 6:24.87 |
| 5 | 6 | Alexa ELLIFF | 10 | Deben | DQ: . |
| 6 | 4 | Jemima WAYMAN | 10 | Deben | 7:03.83 |
| 7 | 2 | Ruby BLACKBURNE | 10 | Watford SC | 6:52.51 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 9 | Isobel BETTLEY | 10 | Halstead | 6:28.31 |
| 2 | 11 | Madeline WRIGHT | 11 | UEA Norwich | 6:04.52 |
| 3 | 13 | Nellie EASTLAND | 11 | Bishop Stort | 6:06.01 |
| 4 | 15 | Ella CHOWN | 11 | Co St Albans | 5:52.06 |
| 5 | 14 | Katie HARRISON | 11 | Potters Bar | 5:58.37 |
| 6 | 12 | Grace MADSEN | 11 | UEA Norwich | 6:14.77 |
| 7 | 10 | Abbie BARNWELL | 11 | Team Luton | 6:20.84 |
| 8 | 8 | Eve WRIGHT | 10 | Co Peterboro | 6:17.86 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 17 | Charlotte MATTHEWS | 12 | Bishop Stort | 5:53.88 |
| 2 | 19 | Bryony UMFREVILLE | 12 | Basildon Ph | 5:50.99 |
| 3 | 21 | Sophie TAYLOR | 12 | St Felix Sch | 5:57.81 |
| 4 | 23 | Olivia NORMAN | 11 | Colchester | 5:54.47 |
| 5 | 22 | Josie PRETIOUS-WHITE | 12 | Bishop Stort | 5:45.88 |
| 6 | 20 | Maisie EASTER | 11 | UEA Norwich | 5:47.86 |
| 7 | 18 | Sophie CROWTHER | 11 | Co Peterboro | 5:52.74 |
| 8 | 16 | Anna BLAKELEY | 11 | Co Peterboro | 5:45.11 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 25 | Megan PYE | 11 | UEA Norwich | 5:58.03 |
| 2 | 27 | Lucie PECK | 11 | UEA Norwich | 5:43.98 |
| 3 | 29 | Tilly ANEMA | 12 | Norwich Swan | 5:40.17 |
| 4 | 31 | Hannah MCNAUL | 13 | West Suffolk | 5:39.93 |
| 5 | 30 | Annabelle KITCHING | 12 | Chelmsford | 5:31.53 |
| 6 | 28 | Chloe LENCE | 12 | Modernians | 5:37.43 |
| 7 | 26 | Holly JASZKIEWICZ | 12 | Co Peterboro | 5:37.68 |
| 8 | 24 | Kaelah LAWSON | 11 | Modernians | 5:44.17 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 33 | Sophie PICKERING | 13 | teamipswich | : . |
| 2 | 35 | Peyton EWBANK | 13 | Norwich Swan | : . |
| 3 | 37 | Gemma TROTT | 14 | Modernians | : . |
| 4 | 39 | Tegan WOLLASTON | 14 | Cheshunt | : . |
| 5 | 38 | Rebecca KITCHING | 13 | Chelmsford | : . |
| 6 | 36 | Georgina CURTIS | 13 | Mid Beds | : . |
| 7 | 34 | Amelia MONAGHAN | 11 | Co Peterboro | : . |
| 8 | 32 | Mia LEECH | 11 | Co Peterboro | : . |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 41 | Katie CROWTHER | 14 | Co Peterboro | : . |
| 2 | 43 | Lauren COLTON | 14 | Witham Dolph | : . |
| 3 | 45 | Poppy RICHARDSON | 12 | Co Peterboro | : . |
| 4 | 47 | Charlotte ASHWIN | 13 | Mid Beds | : . |
| 5 | 46 | Jordanne SILLITOE | 14 | West Suffolk | : . |
| 6 | 44 | Amy YOUNG | 14 | Bishop Stort | : . |
| 7 | 42 | Chantal SMITH | 14 | Team Luton | : . |
| 8 | 40 | Nathalie REUSS | 13 | Co Peterboro | : . |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 49 | Millie EMMANS | 14 | Co Cambridge | : . |
| 2 | 51 | Aiyana LAWSON | 13 | Modernians | : . |
| 3 | 53 | Hanna JASZKIEWICZ | 14 | Co Peterboro | : . |
| 4 | 55 | Katherine BROWN | 14 | Co Peterboro | : . |
| 5 | 54 | Brooke FROST | 13 | Basildon Ph | : . |
| 6 | 52 | Christie WOODS | 13 | Co Peterboro | : . |
| 7 | 50 | Rachel WELLINGS | 14 | Co Peterboro | : . |
| 8 | 48 | Shannon STOTT | 13 | Co St Albans | : . |