EVENT 204 Open/Male 100m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 3 | 2 | George BEILBY-WOODWARD | 10 | Co Leeds | 1:58.43 |
| 4 | 4 | Theo SIRA | 10 | Co Leeds | 1:50.00 |
| 5 | 3 | Francis SALTHOUSE | 10 | Co Sheffield | 1:51.80 |
| 6 | 1 | Ollie FOTHERGILL | 9 | Co Sheffield | 2:25.00 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 6 | Alistair SALTHOUSE | 12 | Co Sheffield | 1:44.05 |
| 2 | 8 | Mason CAMERON | 13 | Co Sheffield | 1:42.77 |
| 3 | 10 | Noah SHEPHARD | 12 | Co Sheffield | 1:38.44 |
| 4 | 12 | Barney HOBBS | 11 | Co Leeds | 1:31.22 |
| 5 | 11 | Henry PATTERSON | 10 | Co Leeds | 1:34.43 |
| 6 | 9 | Devon BRADSHAW | 10 | Co Sheffield | 1:40.00 |
| 7 | 7 | Lewis LUNG | 10 | Co Leeds | 1:44.01 |
| 8 | 5 | Elias BAYARRI | 10 | Co Sheffield | 1:46.71 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 14 | Tomas BICKERS | 12 | Co Leeds | 1:28.07 |
| 2 | 16 | Euan CARMODY | 10 | Co Leeds | 1:26.30 |
| 3 | 18 | Ted WINGFIELD | 10 | Co Leeds | 1:25.09 |
| 4 | 20 | Dyfan PRICE-CLISHEM | 13 | Nofio P.B.P | 1:23.80 |
| 5 | 19 | Owen TEMPEST | 12 | Co Leeds | 1:24.54 |
| 6 | 17 | Benjamin CLARK | 12 | Co Leeds | 1:26.00 |
| 7 | 15 | Oscar CALAM | 10 | Co Leeds | 1:26.96 |
| 8 | 13 | Liam LI | 9 | Co Leeds | 1:30.56 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 22 | Leo CLEGG | 12 | Conwy | 1:23.57 |
| 2 | 24 | George KING | 11 | Co Leeds | 1:22.66 |
| 3 | 26 | Noah DARNELL | 12 | Co Leeds | 1:21.87 |
| 4 | 28 | Abdullah MOKHLISSE | 14 | Chapeltown | 1:20.90 |
| 5 | 27 | Zachary WHITTAKER | 11 | Co Leeds | 1:21.25 |
| 6 | 25 | Enzo SHILAND-GRIFFITHS | 13 | Caernarfon | 1:22.40 |
| 7 | 23 | Hogan LAM | 12 | Co Leeds | 1:23.50 |
| 8 | 21 | Demilade AYEMOWA | 13 | Co Leeds | 1:23.70 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 30 | Harrison WAKE | 12 | Co Leeds | 1:19.65 |
| 2 | 32 | Jacob JONES | 12 | Co Leeds | 1:19.20 |
| 3 | 34 | Jeffrey LANGE | 12 | Co Leeds | 1:17.49 |
| 4 | 36 | Oscar O'DONNELL | 12 | Co Leeds | 1:12.76 |
| 5 | 35 | Callum FOZARD | 13 | Co Leeds | 1:14.49 |
| 6 | 33 | Oscar HUSSEY | 12 | Co Leeds | 1:18.58 |
| 7 | 31 | Olaf GRUDOWSKI | 12 | Co Leeds | 1:19.30 |
| 8 | 29 | Oliver BARKER | 11 | Co Leeds | 1:20.03 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 38 | Jackson CLARKE | 14 | Co Leeds | 1:10.19 |
| 2 | 40 | Tomos OWEN | 17 | Caernarfon | 1:08.90 |
| 3 | 42 | Alfie BIE | 15 | Connahs Quay | 1:07.00 |
| 4 | 44 | Lucas THOMAS | 15 | Conwy | 1:02.91 |
| 5 | 43 | Ewan LEONARD | 15 | Conwy | 1:04.77 |
| 6 | 41 | Matei STOICESCU | 14 | Co Leeds | 1:07.97 |
| 7 | 39 | Reuben HARRISON | 14 | Co Leeds | 1:09.64 |
| 8 | 37 | Owen WILLIAMS | 14 | Caernarfon | 1:11.15 |