EVENT 104 Open/Male 100m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 2 | Tyler LAVENDER | 11 | Team Luton | |
| 3 | 4 | Maxim COLLINSON | 12 | Team Luton | |
| 4 | 6 | Alexandru ZAHARIA | 10 | Ealing | |
| 5 | 5 | Finlay AUSTWICK | 10 | Flitwick | |
| 6 | 3 | Nathaniel NG | 14 | Ealing | |
| 7 | 1 | Christopher ROCHOWSKI | 9 | Linslade | |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 8 | Alexander MCKAY | 11 | Epping For't | 1:50.79 |
| 2 | 10 | Renwa ARIA | 13 | Epping For't | 1:45.33 |
| 3 | 12 | Theo RAWNSLEY | 9 | Harpenden | 1:40.41 |
| 4 | 14 | Filip BOCHENKO | 12 | Ealing | 1:39.82 |
| 5 | 13 | Oscar MCILVANEY | 11 | Flitwick | 1:40.14 |
| 6 | 11 | Sebastian FRASER | 11 | Flitwick | 1:45.32 |
| 7 | 9 | Jack MAY | 13 | Linslade | 1:46.39 |
| 8 | 7 | Kai DE JUAN ENGLUND | 12 | Epping For't | 2:00.00 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 16 | Luke THICKENS | 11 | Linslade | 1:36.22 |
| 2 | 18 | Joshua BETT | 13 | Flitwick | 1:33.84 |
| 3 | 20 | Jack ROBERTSON | 12 | Flitwick | 1:31.85 |
| 4 | 22 | Marcus XU | 13 | Linslade | 1:27.20 |
| 5 | 21 | Arthur JUVILER-BACON | 10 | Linslade | 1:27.90 |
| 6 | 19 | Theo TSANG | 12 | Ealing | 1:33.38 |
| 7 | 17 | Guillaume TITOT | 14 | Epping For't | 1:34.65 |
| 8 | 15 | Arya ZOLFAGHARI | 12 | Epping For't | 1:36.70 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 24 | David KANDELAKI | 13 | Linslade | 1:24.00 |
| 2 | 26 | Jack COX | 12 | Ealing | 1:17.70 |
| 3 | 28 | Adithya BANGERA | 14 | Epping For't | 1:17.14 |
| 4 | 30 | Ayden ROUMILHAC | 13 | Willesden | 1:16.10 |
| 5 | 29 | Elijah FISHER | 14 | Linslade | 1:16.40 |
| 6 | 27 | Casey NDLOVU | 15 | Bo Southend | 1:17.40 |
| 7 | 25 | Jack CANHAM | 13 | Team Luton | 1:23.61 |
| 8 | 23 | Victor MAITRET | 11 | Ealing | 1:26.00 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 32 | Casper WHITTAKER | 12 | Biggleswade | 1:14.80 |
| 2 | 34 | Jack LEES | 12 | Epping For't | 1:14.20 |
| 3 | 36 | Philipp VITKOVSKI | 14 | Epping For't | 1:11.46 |
| 4 | 38 | Robert JAMES | 12 | Epping For't | 1:10.75 |
| 5 | 37 | Lewis COX | 13 | Ealing | 1:11.30 |
| 6 | 35 | Alexandru APOSTOL | 16 | Epping For't | 1:12.81 |
| 7 | 33 | Charles HALLAM | 12 | Harpenden | 1:14.23 |
| 8 | 31 | Alidar KOZHAMZHAROV | 13 | Willesden | 1:15.85 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 40 | Emet YAH-KHAI | 15 | Broomfield | 1:09.82 |
| 2 | 42 | Joseph ELLIOTT | 16 | Flitwick | 1:09.60 |
| 3 | 46 | Ben COUPLAND | 22 | Ealing | 1:04.62 |
| 4 | 48 | Stewart BUTLER | 14 | Dunstable | 1:02.56 |
| 5 | 47 | Rhys THOMAS | 16 | Linslade | 1:03.00 |
| 6 | 45 | Kacper NOWOSIELSKI | 13 | Ealing | 1:05.20 |
| 7 | 41 | Isaac GOLD | 16 | Broomfield | 1:09.60 |
| 8 | 39 | Jake BOWDEN | 17 | Ealing | 1:10.66 |