EVENT 303 Female MC 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 3 | 1 | Merryn Binnie | 15 | S6 | Swim-IT | 8:00.39 |
| 4 | 2 | Josie Johnson | 15 | S8 | RichmondDale | 7:52.70 |
| 5 | 3 | Caitlin Trevor | 21 | S14 | Kingston Roy | 7:37.66 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 4 | Rose Webb | 13 | S6 | Northampton | 7:05.78 |
| 1 | 5 | Iona Winnifrith | 13 | S7 | Tonbridge | 6:45.44 |
| 2 | 6 | Maisie Catt | 15 | S7 | RichmondDale | 6:31.84 |
| 3 | 7 | Samantha Lewis | 32 | S8 | Satellite | 6:29.64 |
| 4 | 8 | Genevieve Hunter | 22 | S8 | Mid Sussex | 6:19.95 |
| 5 | 9 | Ida Corcoran | 15 | S9 | Flitwick | 6:16.51 |
| 6 | 10 | Fern Sneddon | 18 | S6 | GBR - RTWS | 6:02.70 |
| 7 | 11 | Ella Williams | 17 | S13 | Swindon | 5:56.48 |
| 8 | 13 | Scarlett Humphrey | 19 | S11 | GBR - NHNA | 5:40.80 |
| 9 | 12 | Katie Pake | 16 | S10 | Carnegie | 5:52.47 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 15 | Charlotte Hyde | 22 | S7 | GBR - ENSL | 5:36.34 |
| 1 | 14 | Eliza Humphrey | 19 | S11 | GBR - NHNA | 5:38.48 |
| 2 | 16 | Lily Herring | 16 | S10 | Norfolk Vikg | 5:36.33 |
| 3 | 17 | Camilla Bitz Witt | 21 | S9 | DENMARK | 5:36.00 |
| 4 | 18 | Abigail Wickens | 17 | S8 | Flitwick | 5:34.90 |
| 5 | 19 | Ela Letton-Jones | 18 | S12 | GBR - SGPY | 5:33.01 |
| 6 | 20 | Celine Vermaut | 25 | S14 | BELGIUM | 5:28.53 |
| 7 | 21 | Sabrina Duchesne | 23 | S7 | CANADA | 5:20.59 |
| 8 | 22 | Eva French | 17 | S10 | GBR - NUNM | 5:19.00 |
| 9 | 23 | Evie Lambert | 17 | S9 | Bo Kirklees | 5:16.57 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 24 | Lily Rice | 20 | S8 | GBR - PEMY | 5:16.30 |
| 1 | 25 | Meghan Willis | 17 | S9 | GBR - TDOY | 5:14.85 |
| 2 | 26 | Rebecca Lewis | 21 | S10 | GBR - RCTY | 5:14.47 |
| 3 | 27 | Isabella Haynes | 16 | S9 | S Bournem'th | 5:13.08 |
| 4 | 28 | Rebecca Hardy-Bishop | 24 | S12 | Jersey | 5:12.88 |
| 5 | 29 | Brooklyn Hale | 14 | S9 | Cockermouth | 5:11.42 |
| 6 | 30 | Mira Jeanne Maack | 20 | S8 | GERMANY | 5:07.55 |
| 7 | 31 | Katarina Roxon | 31 | S9 | CANADA | 5:06.72 |
| 8 | 32 | Stephanie Booth | 21 | S10 | Bo Kirklees | 5:02.79 |
| 9 | 33 | Amber Haycock | 17 | S10 | GBR - NHNA | 5:02.66 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 35 | Nahia Zudaire Borrezo | 20 | S8 | SPAIN | 5:01.33 |
| 1 | 34 | Liesette Bruinsma | 24 | S11 | NETHERLANDS | 5:02.19 |
| 2 | 36 | Beatriz LeridaMaldonad | 19 | S9 | SPAIN | 4:57.88 |
| 3 | 37 | Brock Whiston | 28 | S8 | GBR - BACL | 4:57.87 |
| 4 | 38 | Taylor Winnett | 25 | S10 | USA | 4:52.27 |
| 5 | 39 | Alice Tai | 25 | S8 | GBR - EALL | 4:49.01 |
| 6 | 40 | Faye Rogers | 22 | S10 | GBR - NUAX | 4:41.06 |
| 7 | 41 | Toni Shaw | 21 | S9 | GBR - NUAX | 4:39.32 |
| 8 | 42 | Pernilla Lindberg | 30 | S14 | SWEDEN | 4:38.87 |
| 9 | 43 | Aurelie Rivard | 28 | S10 | CANADA | 4:24.08 |