EVENT 123 Boys 16/17 Yrs 100m Breaststroke - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 2 | Oliver Cashin | 16 | Cambs | 1:09.22 |
| 1 | 4 | Rio Quarry | 17 | Lancashire | 1:08.23 |
| 2 | 6 | Adam Hardy | 16 | Suffolk | 1:07.84 |
| 3 | 8 | Jackson O'Rourke | 16 | Northants | 1:07.70 |
| 4 | 10 | Timur Gulyiyen | 17 | Berks&SBucks | 1:06.92 |
| 5 | 9 | Charlie Trotman | 16 | Surrey | 1:07.27 |
| 6 | 7 | Samuel Bryan | 17 | Essex | 1:07.82 |
| 7 | 5 | Thomas Leman | 16 | Kent | 1:07.88 |
| 8 | 3 | William Beukenholdt | 17 | N & Durham | 1:08.27 |
| 9 | 1 | Sean Barrett | 16 | Swim Wales W | 1:09.95 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club/Country | Time |
| 0 | 12 | Finnian Trehane | 16 | Dorset | 1:06.61 |
| 1 | 14 | William Bell | 16 | Leics | 1:05.79 |
| 2 | 16 | Andrew Macintosh | 17 | Scot West | 1:04.42 |
| 3 | 18 | Oliver Taverner | 17 | Devon | 1:03.85 |
| 4 | 20 | Archie Goodburn | 17 | Scot East | 1:01.52 |
| 5 | 19 | Kyle Booth | 17 | Swim Wales E | 1:03.47 |
| 6 | 17 | William Mitchell | 16 | Somerset | 1:04.40 |
| 7 | 15 | Tommy Donovan | 17 | Middlesex | 1:04.74 |
| 8 | 13 | Arnold Marton | 17 | Ox & N Bucks | 1:05.99 |
| 9 | 11 | Jake Lambert | 17 | Yorkshire | 1:06.92 |