EVENT 204 Mixed 800m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 2 | 52 | Sara BOUKHTOUCHE | 10 | | Ealing | |
| 3 | 50 | Nathaniel NG | 15 | | Ealing | |
| 4 | 21 | Ellis GLANTZ | 11 | | Putteridge | |
| 5 | 49 | Charlotte FITZHERBERT | 12 | | Wycombe Dist | |
| 6 | 51 | Anna INGRAM | 15 | | Ealing | |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 3 | Olivia PIASKOWSKA | 13 | | Dunstable | |
| 2 | 15 | Ella KOLOBIUS | 13 | | Team Luton | |
| 3 | 13 | Isabella ELO | 15 | | Saffron Wald | |
| 4 | 7 | Jack COX | 13 | | Ealing | |
| 5 | 16 | Charlotte FIELDS | 12 | | Berkhamsted | |
| 6 | 9 | Chloe FINCH | 14 | | Biggleswade | |
| 7 | 5 | Lyle SULLIVAN | 12 | | Saffron Wald | |
| 8 | 19 | Janneke VAN CALSTEREN | 14 | | Co Milton K | |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 12 | Abraham COHEN WRAY | 11 | | Berkhamsted | |
| 2 | 20 | Isabelle WATSON | 11 | | Dunstable | |
| 3 | 18 | Ruth BISCOE | 12 | | Team Luton | |
| 4 | 22 | Charlotte TAPE | 10 | | Bo Southend | |
| 5 | 14 | Charlotte ROSS AREVALO | 15 | | Harpenden | |
| 6 | 11 | Nathan JOHNSON | 14 | | Biggleswade | |
| 7 | 8 | Lucy BISCOE | 10 | | Team Luton | |
| 8 | 10 | Matthew HORTON | 16 | | Dunstable | |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 23 | Theo RAWNSLEY | 10 | | Harpenden | |
| 2 | 26 | Thea SLATER | 14 | | Team Luton | |
| 3 | 28 | Tyatt COLE | 11 | | Bo Southend | |
| 4 | 31 | Cora PAYNE | 11 | | Dunstable | |
| 5 | 30 | Elliott WHITEHEAD | 14 | | Harpenden | |
| 6 | 29 | Emily TAPE | 12 | | Bo Southend | 11:43.37 |
| 7 | 27 | Yaroslav SEMKIN | 14 | | Co Milton K | 12:06.37 |
| 8 | 24 | William ROBERTS | 26 | S14 | Peterbo SPG | 12:43.20 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 32 | Rahil ABWOOLI | 12 | | TigersJersey | |
| 2 | 34 | Cerys LONG | 14 | | Co Milton K | |
| 3 | 37 | Adam MESSIS | 14 | | Ealing | 10:28.10 |
| 4 | 39 | Megan MCKAY | 16 | | Leighton Buz | 10:15.40 |
| 5 | 38 | George RHODES | 15 | | Team Luton | 10:25.20 |
| 6 | 36 | Thomas HOGBEN | 13 | | Co Milton K | |
| 7 | 35 | Harvey PEACOCK | 12 | | Bo Southend | 10:53.30 |
| 8 | 33 | Sophie GARLAND | 13 | | Harpenden | 11:13.52 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 41 | Lucy ALEXANDER | 16 | | Harpenden | 10:02.72 |
| 2 | 43 | Samuel CHILDS | 13 | | Berkhamsted | 9:55.23 |
| 3 | 46 | Connie FLITTON | 15 | | Dunstable | 9:40.87 |
| 4 | 54 | Zente BUZSIK | 15 | | Haringey | 9:29.21 |
| 5 | 47 | Hayden JOHNSON | 16 | | Biggleswade | 9:40.70 |
| 6 | 44 | Evie ARMSTRONG | 13 | | Dunstable | 9:51.50 |
| 7 | 42 | Victoria GRANT | 12 | | TigersJersey | 10:00.70 |
| 8 | 40 | Libby FLITTON | 13 | | Dunstable | 10:07.44 |