EVENT 209 Womens Open 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 3 | 2 | Ella Took | 14 | Tynemouth | 4:24.43 |
| 4 | 4 | Charlotte Rens | 15 | Co Liverpool | 4:24.11 |
| 5 | 3 | Lucy Hedley | 14 | Tynemouth | 4:24.22 |
| 6 | 1 | Millie Checkley | 14 | Co Birm'ham | 4:24.55 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 6 | Megan Barnes | 15 | Barnes SC | 4:23.44 |
| 1 | 8 | Rebecca Howell | 15 | Basildon Ph | 4:23.30 |
| 2 | 10 | Sapphira Gabbani | 15 | Co Sheffield | 4:21.57 |
| 3 | 12 | Olivia Butler | 15 | Co Bristol | 4:21.45 |
| 4 | 14 | Meghan Byrne | 18 | Barnet Copt | 4:19.12 |
| 5 | 13 | Fleur Lewis | 15 | Barnet Copt | 4:19.23 |
| 6 | 11 | Kirstie Flynn | 15 | Leatherhead | 4:21.45 |
| 7 | 9 | Isobel Bryant | 15 | Guildford Ct | 4:23.01 |
| 8 | 7 | Alexis Lambropoulos | 14 | Camden Swiss | 4:23.36 |
| 9 | 5 | Merissa Booth | 13 | Wycombe Dist | 4:24.07 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 16 | Milly Boulding | 14 | Bo Kirklees | 4:18.67 |
| 1 | 18 | Alice Thickett | 16 | Co Sheffield | 4:18.15 |
| 2 | 20 | Rachel Bethel | 18 | Bangor IRL | 4:18.02 |
| 3 | 22 | Abbie Bowden | 16 | KingstonHull | 4:17.44 |
| 4 | 24 | Isobel Griffiths | 19 | Birm'ham Uni | 4:17.20 |
| 5 | 23 | Jemima Hall | 17 | Wycombe Dist | 4:17.43 |
| 6 | 21 | Leah Crisp | 17 | Co Leeds | 4:17.86 |
| 7 | 19 | Mia Slevin | 15 | Derventio | 4:18.03 |
| 8 | 17 | Thea O'Keefe | 18 | Poole | 4:18.43 |
| 9 | 15 | Beatrice Varley | 15 | Hamilton UAE | 4:18.93 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 27 | Mia Leech | 16 | Co Peterboro | 4:16.79 |
| 1 | 31 | Mollie Wright | 20 | Nova Cent'n | 4:16.03 |
| 2 | 35 | Freya Colbert | 14 | Nova Cent'n | 4:14.76 |
| 3 | 39 | Alice Dearing | 21 | Loughboro Un | 4:11.43 |
| 4 | 43 | Abbie Wood | 19 | Loughboro Un | 4:06.43 |
| 5 | 41 | Sharni Robinson | 16 | StPeters AUS | 4:10.53 |
| 6 | 37 | Emilia Sansome | 17 | Wycombe Dist | 4:12.48 |
| 7 | 33 | Nicole Ryan | 20 | Co Oxford | 4:15.31 |
| 8 | 29 | Caitlin Mackay | 17 | Wycombe Dist | 4:16.38 |
| 9 | 25 | Emily Clarke | 21 | Loughboro Un | 4:17.02 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 28 | Georgina Dennis | 16 | Mt Kelly | 4:16.74 |
| 1 | 32 | Phyllida Britton | 21 | Ealing | 4:15.51 |
| 2 | 36 | Betsy Wizard | 15 | Northampton | 4:12.51 |
| 3 | 40 | Michaella Glenister | 16 | Leic Sharks | 4:10.86 |
| 4 | 44 | Holly Hibbott | 19 | Stockport Mo | 4:02.25 |
| 5 | 42 | Polly Holden | 19 | Nova Cent'n | 4:08.54 |
| 6 | 38 | Laura Stephens | 19 | Plymouth Lea | 4:12.16 |
| 7 | 34 | Lola Davison | 15 | Newcastle | 4:15.14 |
| 8 | 30 | Maisie Elliott | 15 | Co Leicester | 4:16.21 |
| 9 | 26 | Rebecca Thornton | 18 | Bo Kirklees | 4:16.90 |