EVENT 504 Female 12 Yrs/Under 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 3 | 2 | Sophie Walgate | 11 | Northampton | 6:56.90 |
| 4 | 4 | Savannah Koriya | 11 | Northampton | 6:47.90 |
| 5 | 3 | Chloe Richardson | 11 | Northampton | 6:50.80 |
| 6 | 1 | Eliza Groom | 11 | Corby | 7:31.20 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 6 | Leah Whitehead | 12 | Northampton | 6:29.90 |
| 2 | 8 | Isabelle Csibi | 12 | Rushden | 6:15.84 |
| 3 | 10 | Victoria Komorowska | 12 | Corby | 6:07.00 |
| 4 | 12 | Ren Wood | 12 | Corby | 6:01.28 |
| 5 | 11 | Darcy Poole | 12 | Northampton | 6:06.10 |
| 6 | 9 | Annabelle Lucas | 11 | Northampton | 6:13.00 |
| 7 | 7 | Ayla Madden | 12 | Northampton | 6:29.90 |
| 8 | 5 | Merryn Fulford | 12 | Daventry | 6:34.90 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 14 | Jessica Kemp | 12 | Wellingboro | 5:55.90 |
| 2 | 16 | Sophie Quennell | 12 | Northampton | 5:52.30 |
| 3 | 18 | Olivia Fern | 12 | Northampton | 5:27.60 |
| 4 | 20 | Milly Webb | 12 | Northampton | 5:08.50 |
| 5 | 19 | Daria Bielawski | 12 | Northampton | 5:19.20 |
| 6 | 17 | Sophie Rees | 11 | Northampton | 5:31.39 |
| 7 | 15 | Vanessa Meger | 12 | Corby | 5:54.02 |
| 8 | 13 | Lara Cooper | 12 | Northampton | 6:00.30 |