EVENT 304 Women MC 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 2 | 1 | Megan LAMB | 09 | Lincoln Vulc | 6:12.59 |
| 3 | 3 | Amy STRATTON | 05 | Boston | 6:03.37 |
| 4 | 5 | Sigourney BOLTON | 09 | South Lincs | 5:59.22 |
| 5 | 4 | Rianna ABBOTT | 08 | Grantham | 6:02.05 |
| 6 | 2 | Madison LAMB | 06 | Lincoln Vulc | 6:07.18 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 7 | Sophie COOKSEY | 10 | Louth | 5:56.65 |
| 2 | 9 | Kitty LAMB | 11 | South Lincs | 5:55.18 |
| 3 | 11 | Evie DICKINSON | 08 | Louth | 5:46.46 |
| 4 | 13 | Lucy WILSON | 10 | South Lincs | 5:46.38 |
| 5 | 12 | Olivia SPENCER | 06 | Lincoln Vulc | 5:46.41 |
| 6 | 10 | Skye HOLMES | 10 | Louth | 5:54.84 |
| 7 | 8 | Helena FIELD | 09 | Louth | 5:55.72 |
| 8 | 6 | Penelope BAXTER | 05 | Deepings | 5:57.16 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 15 | Hannah BRUCE | 09 | South Lincs | 5:43.90 |
| 2 | 17 | Daniela BRINGEMAN | 07 | South Lincs | 5:40.06 |
| 3 | 19 | Lillie HAMILTON | 08 | South Lincs | 5:34.54 |
| 4 | 21 | Grace MACDONALD | 09 | Grantham | 5:29.27 |
| 5 | 20 | Evelyn JACKSON | 08 | Lincoln Vulc | 5:30.12 |
| 6 | 18 | Alexandra HALLAM-STOTT | 06 | Grantham | 5:34.90 |
| 7 | 16 | Erin INGHAM | 08 | Louth | 5:41.77 |
| 8 | 14 | Gracie-May COLE | 08 | Co Lincoln P | 5:44.68 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 23 | Olivia ANSTEY | 08 | Louth | 5:19.06 |
| 2 | 25 | Francesca HALLAM-STOTT | 07 | Grantham | 5:13.82 |
| 3 | 27 | Grace TURNER | 07 | Grantham | 5:11.60 |
| 4 | 29 | Megan SPEIRS | 04 | Co Lincoln P | 5:03.30 |
| 5 | 28 | Beatrice FINCH | 06 | South Lincs | 5:06.10 |
| 6 | 26 | Chloe HOPKINSON | 05 | Grantham | 5:12.08 |
| 7 | 24 | Lilli-Rose CARR | 09 | Co Lincoln P | 5:17.60 |
| 8 | 22 | Mollie BRIGGS | 05 | South Lincs | 5:19.51 |