EVENT 125 Open/Male 12/13 100m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 1 | Noah Bielby | 13 | Northants | 1:21.66 |
| 2 | 3 | Zach Montgomery | 13 | Norfolk | 1:13.63 |
| 3 | 5 | Rocco Wilson | 13 | Cumbria | 1:13.33 |
| 4 | 7 | Elliott Hughes | 13 | Cheshire | 1:11.18 |
| 5 | 6 | Lachlan Bullough | 13 | Scot North | 1:12.36 |
| 6 | 4 | Gethin Jenks | 13 | Wiltshire | 1:13.34 |
| 7 | 2 | Sam Good | 13 | Shropshire | 1:18.46 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 0 | 9 | William Davies | 13 | Cornwall | 1:10.38 |
| 1 | 11 | S Newman-Baronius | 13 | Ox & N Bucks | 1:08.68 |
| 2 | 13 | Elliot Griffiths | 13 | Staffs | 1:07.55 |
| 3 | 15 | Oscar Jakeways | 13 | Gloucs | 1:06.58 |
| 4 | 17 | Damian Fraczek-Krygier | 13 | Dorset | 1:04.83 |
| 5 | 16 | Jacob Bacon | 13 | Cambs | 1:06.37 |
| 6 | 14 | Lucas Douglas | 12 | SW Wales | 1:07.53 |
| 7 | 12 | Oliver Ashman | 13 | Leics | 1:08.17 |
| 8 | 10 | Luke Owens | 13 | Bedfordshire | 1:09.68 |
| 9 | 8 | Aaron Sadler | 13 | Lincolnshire | 1:10.39 |