EVENT 304 Boys 12 Yrs/Under 50m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 2 | 1 | Thomas KINNEAR | 10 | Grantham | |
| 3 | 2 | William CASH | 13 | Deepings | |
| 4 | 3 | Woody CLARK | 14 | Grantham | 1:30.00 |
| 5 | 4 | Benjamin SHEARN | 14 | Grantham | 1:30.00 |
| 6 | 6 | Derrin BROCKLEBANK | 14 | Grantham | 1:20.00 |
| 7 | 11 | Henry DOLAN | 13 | Grantham | 1:05.95 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 12 | Henry COATEN | 11 | Grantham | 1:04.30 |
| 2 | 13 | Arlo HAMER | 12 | Co Lincoln P | 1:02.66 |
| 3 | 14 | Oscar CHEN-REES | 12 | Grantham | 1:01.49 |
| 4 | 17 | Noah SKINNER | 11 | Deepings | 57.33 |
| 5 | 18 | Logan MEGGETT | 10 | Co Lincoln P | 57.00 |
| 6 | 19 | George WOODHEAD | 13 | Retford | 55.24 |
| 7 | 20 | Tristan EKE | 11 | Co Lincoln P | 54.67 |
| 8 | 22 | Bobby WALLIS | 12 | Co Lincoln P | 53.65 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 23 | Oscar WOOD | 13 | Lincoln Vulc | 52.96 |
| 2 | 24 | Bertie ROSE | 13 | Lincoln Vulc | 52.42 |
| 3 | 26 | Owen THOMAS | 11 | Retford | 50.89 |
| 4 | 27 | Elliot GLEAVE | 13 | Grantham | 50.43 |
| 5 | 28 | Michael BUNN | 11 | Lincoln Vulc | 50.37 |
| 6 | 29 | Isacc BADGER-DONALDSON | 13 | Deepings | 49.90 |
| 7 | 30 | George LEONARD | 12 | Grantham | 49.90 |
| 8 | 31 | Dan PALMER | 13 | Co Lincoln P | 49.38 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 33 | Barnaby DURANT | 13 | Grantham | 47.76 |
| 2 | 34 | Leo BARNETT | 12 | Grantham | 46.00 |
| 3 | 35 | Evan NIXON | 11 | Lincoln Vulc | 45.90 |
| 4 | 38 | Zachary WILSON | 12 | Lincoln Vulc | 45.00 |
| 5 | 39 | Joshua KIM | 12 | Grantham | 44.95 |
| 6 | 40 | Kieran BLOOR | 11 | Co Lincoln P | 44.90 |
| 7 | 41 | Zachary BARROWCLIFFE | 11 | Retford | 44.86 |
| 8 | 43 | Yu Ching (Eugene) CHEU | 11 | Grantham | 44.04 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 44 | Luca HALLAM | 12 | Grantham | 43.98 |
| 2 | 45 | Thomas HILLSON | 13 | Grantham | 42.70 |
| 3 | 47 | Cole COOPER | 12 | Co Lincoln P | 42.40 |
| 4 | 49 | Corey HESELTINE | 12 | Retford | 41.27 |
| 5 | 50 | Henry WILLERTON | 13 | Boston | 41.01 |
| 6 | 51 | Fabian KOLASA | 11 | Grantham | 39.60 |
| 7 | 52 | Samuel NICHOLS | 12 | Grantham | 39.48 |
| 8 | 53 | Connor SMITH | 10 | Grantham | 39.14 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 56 | Oliver CLARKE | 12 | Deepings | 38.68 |
| 2 | 59 | James CASH | 10 | Deepings | 35.81 |
| 3 | 62 | James HUCKLE | 11 | Lincoln Vulc | 34.73 |
| 4 | 64 | Riley HAMER | 10 | Co Lincoln P | 33.90 |
| 5 | 63 | Robbie DUFF | 11 | Lincoln Vulc | 34.10 |
| 6 | 61 | Thomas COLLINS | 10 | Retford | 34.80 |
| 7 | 58 | Reuben MEADOWS | 10 | Retford | 37.07 |
| 8 | 54 | Oliver WILKINSON | 12 | Lincoln Vulc | 38.71 |