EVENT 123 Boys 16/17 Yrs 100m Breaststroke - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 0 | 2 | Harrison Stevens | 96 | Sussex | 1:10.57 |
| 1 | 4 | Zak Dawson | 96 | N & Durham | 1:09.61 |
| 2 | 6 | Matthew Law | 96 | Yorkshire | 1:09.30 |
| 3 | 8 | Ben Baston | 96 | Swim Wales E | 1:08.74 |
| 4 | 10 | Thomas Holwarth | 97 | Notts | 1:08.10 |
| 5 | 9 | Caleb Hughes | 95 | Herts | 1:08.17 |
| 6 | 7 | Jacob Darby | 96 | Worcs | 1:08.79 |
| 7 | 5 | Harold Pearson | 97 | Kent | 1:09.60 |
| 8 | 3 | Sam Woodruff | 96 | Berks&SBucks | 1:09.68 |
| 9 | 1 | Jordan Hughes | 97 | Swim Wales W | 1:11.90 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 0 | 12 | Aneirin Baker | 96 | Lancashire | 1:07.10 |
| 1 | 14 | Michael Esnopuf | 96 | Ox & N Bucks | 1:05.87 |
| 2 | 16 | Paul Achkar | 96 | Middlesex | 1:05.20 |
| 3 | 18 | Daniel Lim | 96 | Scot East | 1:04.40 |
| 4 | 20 | Giovanni Guarino | 96 | Hampshire | 1:03.77 |
| 5 | 19 | Charlie Attwood | 97 | Somerset | 1:04.21 |
| 6 | 17 | Dominic Holloway | 96 | Surrey | 1:04.50 |
| 7 | 15 | Andrew McFadzean | 97 | Scot West | 1:05.26 |
| 8 | 13 | James Latham | 95 | Derbyshire | 1:05.90 |
| 9 | 11 | Ben Cleaveley | 96 | Cheshire | 1:07.53 |