EVENT 104 Open/Male 12 /Under 50m Butterfly - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 1 | Henry MOSS | 12 | Deepings | |
| 3 | 2 | Henry LEONARD | 9 | Grantham | |
| 4 | 3 | Albie WILSON | 9 | Deepings | |
| 5 | 4 | Ethan BAILEY | 10 | Deepings | |
| 6 | 5 | Laurence DE ROSE | 9 | Deepings | |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 6 | Theo MIDDLETON | 11 | Deepings | |
| 2 | 7 | Ralph MILNE | 10 | Grantham | |
| 3 | 8 | Oscar BEMBRIDGE | 9 | Grantham | |
| 4 | 9 | Oliver FAWCETT | 9 | Grantham | |
| 5 | 10 | Zhengxi (John) GUO | 9 | Grantham | |
| 6 | 11 | George PAYNE | 10 | Deepings | |
| 7 | 12 | Jack PAIGE | 11 | Deepings | |
| 8 | 13 | Henry BOWERS | 10 | Grantham | |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 14 | Oliver PYGOTT-HAMMOND | 10 | Grantham | |
| 2 | 15 | Gilbert NICHOLLS | 9 | Grantham | |
| 3 | 16 | Jack DAWSON | 9 | Deepings | |
| 4 | 17 | Jack CHAMBERS | 9 | Grantham | |
| 5 | 18 | Finlay HODSON | 9 | Deepings | |
| 6 | 19 | Hector BARR | 10 | Deepings | |
| 7 | 20 | Ewan BELL | 10 | Lincoln Vulc | 1:31.25 |
| 8 | 21 | Leo GOODWIN | 12 | Lincoln Vulc | 1:30.00 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 22 | Yousef HAFEZ | 9 | Co Lincoln P | 1:30.00 |
| 2 | 23 | Ethan DANIELS | 11 | Lincoln Vulc | 1:22.30 |
| 3 | 24 | Jenson FRANCIS-SWABY | 10 | Co Lincoln P | 1:15.00 |
| 4 | 25 | Finlay MATHESON | 9 | Co Lincoln P | 1:07.99 |
| 5 | 26 | Ali HAFEZ | 10 | Co Lincoln P | 1:05.00 |
| 6 | 27 | Edward BIRINY | 11 | Lincoln Vulc | 1:03.08 |
| 7 | 28 | Leo FRANCZAK | 10 | Co Lincoln P | 1:02.88 |
| 8 | 30 | Ethan COOK | 10 | Co Lincoln P | 1:00.00 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 31 | Charles BLYTH | 11 | Lincoln Vulc | 58.96 |
| 2 | 32 | Zachary SMITH GOMEZ | 10 | Lincoln Vulc | 58.51 |
| 3 | 33 | Ksawery WRONSKI | 12 | Co Lincoln P | 58.29 |
| 4 | 34 | Felix THORNDIKE | 9 | Lincoln Vulc | 58.00 |
| 5 | 35 | Fox RICHARDSON | 9 | Co Lincoln P | 57.73 |
| 6 | 36 | Benjamin BROWN | 10 | Deepings | 54.86 |
| 7 | 37 | Charlie ARMSTRONG | 12 | Deepings | 54.60 |
| 8 | 38 | James BAILEY | 12 | Deepings | 54.55 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 39 | Ethan PEART | 10 | Deepings | 54.23 |
| 2 | 40 | Max ELDRIDGE | 12 | Co Lincoln P | 52.99 |
| 3 | 41 | Daniel GODDARD | 11 | Grantham | 52.29 |
| 4 | 42 | Lewis CLARKE | 12 | Co Lincoln P | 51.23 |
| 5 | 43 | Ethan MEHTA | 11 | Lincoln Vulc | 51.23 |
| 6 | 44 | Alex HUCKLE | 9 | Co Lincoln P | 50.66 |
| 7 | 45 | Zac RHOADES | 12 | Co Lincoln P | 50.03 |
| 8 | 46 | George DOLAN | 9 | Grantham | 48.17 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 47 | Harrison ABLITT | 11 | Co Lincoln P | 47.83 |
| 2 | 48 | Zachary TOMLINSON | 12 | Co Lincoln P | 47.02 |
| 3 | 49 | Jack ROWSELL | 11 | Co Lincoln P | 46.81 |
| 4 | 50 | Rory MACKFALL | 12 | Lincoln Vulc | 46.54 |
| 5 | 51 | Tom BARRATT | 11 | Gainsborough | 45.71 |
| 6 | 52 | Siddharth SUTHAN | 11 | Co Lincoln P | 45.53 |
| 7 | 53 | Finley RUSHTON | 12 | Co Lincoln P | 45.00 |
| 8 | 54 | George Arthur PYKE | 12 | Gainsborough | 44.22 |
| Heat Number - 8 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 57 | Liam EDMEADES | 10 | Deepings | 40.77 |
| 2 | 59 | Joshua FORSYTH | 12 | Lincoln Vulc | 38.66 |
| 3 | 61 | Freddie HIRST | 11 | Grantham | 37.86 |
| 4 | 63 | Markas PARAPIJONAVICIU | 12 | Grantham | 34.13 |
| 5 | 62 | Toby EDMONDSON | 11 | Grantham | 34.20 |
| 6 | 60 | Henry DOLAN | 12 | Grantham | 38.25 |
| 7 | 58 | Derrin BROCKLEBANK | 12 | Grantham | 39.51 |
| 8 | 56 | William PENNOCK | 12 | Grantham | 43.03 |