EVENT 104 Boys 12 Yrs/Under 50m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 2 | Isacc BADGER-DONALDSON | 10 | Deepings | |
| 3 | 5 | Riley FOX | 12 | Lincoln Vulc | |
| 4 | 6 | Alex NEVARD | 10 | Grantham | |
| 5 | 7 | Thomas BURDOCK | 12 | Deepings | |
| 6 | 8 | Benjamin SHEARN | 9 | Grantham | 1:30.00 |
| 7 | 11 | Thomas HILLSON | 9 | Grantham | 1:20.00 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 12 | Oscar CHEN-REES | 10 | Grantham | 1:20.00 |
| 2 | 13 | Bertie ROSE | 9 | Lincoln Vulc | 1:19.37 |
| 3 | 14 | Oscar WOOD | 10 | Lincoln Vulc | 1:16.82 |
| 4 | 16 | Henry COATEN | 12 | Grantham | 1:15.00 |
| 5 | 17 | Barnaby DURANT | 9 | Grantham | 1:10.00 |
| 6 | 18 | Yu Ching (Eugene) CHEU | 11 | Grantham | 1:10.00 |
| 7 | 19 | Elliot GLEAVE | 10 | Grantham | 1:10.00 |
| 8 | 20 | Joshua KIM | 10 | Grantham | 1:10.00 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 21 | Leo BARNETT | 11 | Grantham | 1:10.00 |
| 2 | 22 | Benjamin GODDARD | 10 | Grantham | 1:10.00 |
| 3 | 23 | Henry DOLAN | 9 | Grantham | 1:06.72 |
| 4 | 24 | George LEONARD | 10 | Grantham | 1:02.96 |
| 5 | 25 | Alfie GROUNSELL | 10 | Retford | 1:00.36 |
| 6 | 26 | Evan NIXON | 11 | Lincoln Vulc | 58.95 |
| 7 | 27 | George WOODHEAD | 9 | Retford | 58.44 |
| 8 | 30 | Arlo HAMER | 10 | Co Lincoln P | 57.00 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 32 | Cole COOPER | 11 | Co Lincoln P | 57.00 |
| 2 | 33 | Bobby WALLIS | 10 | Co Lincoln P | 56.59 |
| 3 | 34 | Michael BUNN | 12 | Lincoln Vulc | 54.55 |
| 4 | 35 | Bobby THAIN | 12 | Skegness | 53.86 |
| 5 | 36 | Zachary WILSON | 11 | Lincoln Vulc | 52.36 |
| 6 | 37 | Charlie ANDERSON | 11 | Retford | 51.29 |
| 7 | 38 | Dan PALMER | 10 | Co Lincoln P | 50.96 |
| 8 | 39 | Owen THOMAS | 12 | Retford | 50.89 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 40 | Henry WILLERTON | 9 | Boston | 49.38 |
| 2 | 42 | Oliver CLARKE | 10 | Deepings | 47.87 |
| 3 | 43 | Ethan DERBY | 12 | Lincoln Vulc | 46.64 |
| 4 | 44 | Finley ROWDING | 12 | Co Lincoln P | 46.03 |
| 5 | 45 | Hugo WARD | 11 | Boston | 45.87 |
| 6 | 46 | Kieran BLOOR | 12 | Co Lincoln P | 45.38 |
| 7 | 47 | Joel SADLER | 12 | Grantham | 45.36 |
| 8 | 48 | Zachary BARROWCLIFFE | 12 | Retford | 44.86 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 49 | Stanley THURLOW | 10 | Lincoln Vulc | 44.72 |
| 2 | 50 | Luca HALLAM | 11 | Grantham | 44.65 |
| 3 | 51 | Oliver WILKINSON | 10 | Lincoln Vulc | 44.31 |
| 4 | 52 | Jonathan GBYLICZEK | 11 | Lincoln Vulc | 44.18 |
| 5 | 53 | Samuel NICHOLS | 11 | Grantham | 42.69 |
| 6 | 54 | Connor SMITH | 12 | Grantham | 42.65 |
| 7 | 55 | Corey HESELTINE | 11 | Retford | 42.43 |
| 8 | 56 | Fabian KOLASA | 12 | Grantham | 42.03 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 58 | Oscar DURANT | 12 | Grantham | 39.74 |
| 2 | 60 | James HUCKLE | 11 | Lincoln Vulc | 38.54 |
| 3 | 64 | Matthew ROBERTS | 12 | Co Lincoln P | 35.53 |
| 4 | 66 | Samuel GREEN | 12 | Retford | 32.42 |
| 5 | 65 | Noah DEWSNAP | 11 | Retford | 33.82 |
| 6 | 61 | Thomas COLLINS | 12 | Retford | 37.48 |
| 7 | 59 | Reuben MEADOWS | 12 | Retford | 38.86 |
| 8 | 57 | Robbie DUFF | 11 | Lincoln Vulc | 41.16 |