EVENT 503 Womens Open 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 3 | 2 | Rebecca Reid | 17 | Aberdeen | 4:27.97 |
| 4 | 4 | Amy West | 15 | Stockport Mo | 4:27.75 |
| 5 | 3 | Charlotte Hall | 17 | Derventio | 4:27.76 |
| 6 | 1 | Caitlin Kilgallen | 17 | Chase | 4:28.03 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 6 | Abbie Bowden | 17 | KingstonHull | 4:27.67 |
| 2 | 8 | Emma Russell | 16 | Heart Of Mid | 4:27.45 |
| 3 | 10 | Alicia Dingle | 17 | Royal Wolv | 4:27.22 |
| 4 | 12 | Anna Smail | 17 | Ellesmere Co | 4:26.91 |
| 5 | 11 | Abbie Low | 17 | Chelmsford | 4:27.17 |
| 6 | 9 | Georgina Dennis | 17 | Mt Kelly | 4:27.34 |
| 7 | 7 | Sapphira Gabbani | 16 | Co Sheffield | 4:27.57 |
| 8 | 5 | Ella Dyson | 15 | Wycombe Dist | 4:27.72 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 14 | Milly Boulding | 15 | Bo Kirklees | 4:25.24 |
| 2 | 16 | Meghan Byrne | 19 | Barnet Copt | 4:24.77 |
| 3 | 18 | Phoebe Griffiths | 19 | Ellesmere Co | 4:24.38 |
| 4 | 20 | Daisy Anderson | 18 | Thanet Swim | 4:23.97 |
| 5 | 19 | Caitlin Mackay | 18 | Wycombe Dist | 4:24.17 |
| 6 | 17 | Chloe Stennett | 17 | Chesterfield | 4:24.74 |
| 7 | 15 | Amy Davies | 17 | SouthCroydon | 4:24.82 |
| 8 | 13 | Mackenzie Whyatt | 17 | Co Peterboro | 4:25.76 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 22 | Rebecca Thornton | 19 | Bo Kirklees | 4:23.76 |
| 2 | 24 | Fleur Lewis | 16 | Barnet Copt | 4:23.68 |
| 3 | 26 | Franka Wilke | 17 | Plymouth Lea | 4:22.86 |
| 4 | 28 | Katie Shanahan | 15 | Co Glasgow | 4:22.63 |
| 5 | 27 | Mia Slevin | 16 | Derventio | 4:22.76 |
| 6 | 25 | Mia Leech | 17 | Co Peterboro | 4:23.24 |
| 7 | 23 | Iona Macleod | 16 | Dun City Aqu | 4:23.72 |
| 8 | 21 | Alice Thickett | 17 | Co Sheffield | 4:23.90 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 30 | Alisha Hawkins | 18 | Stockport Mo | 4:22.31 |
| 2 | 32 | Megan Barnes | 16 | Barnes SC | 4:22.01 |
| 3 | 34 | Emilia Sansome | 18 | Wycombe Dist | 4:21.92 |
| 4 | 36 | Amelia Rodd | 17 | Ellesmere Co | 4:21.21 |
| 5 | 35 | Tamryn Van Selm | 15 | Bromley | 4:21.53 |
| 6 | 33 | Nikki Miller | 19 | Eastkilbride | 4:21.94 |
| 7 | 31 | Jemima Hall | 18 | Wycombe Dist | 4:22.21 |
| 8 | 29 | Maisie Elliott | 16 | Co Leicester | 4:22.63 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 39 | Lauren Wetherell | 17 | Ellesmere Co | 4:20.05 |
| 2 | 43 | Rachel Anderson | 17 | Millfield | 4:18.52 |
| 3 | 47 | Monique Olivier | 21 | Edinburgh Un | 4:17.21 |
| 4 | 51 | Elizabeth Harris | 19 | Stockport Mo | 4:14.46 |
| 5 | 49 | Leah Crisp | 18 | Co Leeds | 4:14.78 |
| 6 | 45 | Michaella Glenister | 17 | Leic Sharks | 4:18.39 |
| 7 | 41 | Maisie Macartney | 18 | Thanet Swim | 4:19.55 |
| 8 | 37 | Meg Finnon | 21 | UniOfStirl | 4:21.10 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 1 | 40 | Freya Colbert | 15 | Nova Cent'n | 4:19.96 |
| 2 | 44 | Madeleine Crompton | 19 | Bath Univ | 4:18.40 |
| 3 | 48 | Kathryn Greenslade | 21 | Edinburgh Un | 4:14.80 |
| 4 | 52 | Holly Hibbott | 20 | Stockport Mo | 4:05.01 |
| 5 | 50 | Hannah Miley | 30 | Aberdeen Per | 4:14.62 |
| 6 | 46 | Emily Clarke | 22 | Loughboro Un | 4:17.54 |
| 7 | 42 | Lola Davison | 16 | Newcastle | 4:18.71 |
| 8 | 38 | Betsy Wizard | 16 | Northampton | 4:20.15 |