EVENT 401 Open/Male 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 1 | Daniel IDCZAK | 9 | | Chadderton | 8:22.20 |
| 1 | 3 | Dexter ROWLANDS | 11 | | Co Leeds | 6:51.00 |
| 2 | 5 | Connor SMITH | 12 | | Conwy | 6:48.70 |
| 3 | 7 | Charlie MACFADYEN | 11 | | Co Leeds | 6:40.00 |
| 4 | 9 | George BEILBY-WOODWARD | 11 | | Co Leeds | 6:35.00 |
| 5 | 8 | Ryker BOYD | 11 | | Co Leeds | 6:40.00 |
| 6 | 6 | Harry TROUSDALE | 12 | | Co Leeds | 6:40.00 |
| 7 | 4 | Harry WILKINSON | 9 | | Co Leeds | 6:50.00 |
| 8 | 2 | Jack WILLIMENT-BARR | 10 | | Co Leeds | 7:50.00 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 11 | Toby BIGWOOD | 10 | | Blackburn | 6:29.79 |
| 1 | 13 | Arshak RAHMANI | 11 | | Co Leeds | 6:26.02 |
| 2 | 15 | Finley GILL | 10 | | Co Leeds | 6:20.00 |
| 3 | 17 | Daniel RAWLINGS | 12 | | Co Leeds | 6:15.00 |
| 4 | 19 | Harrison NORTON | 12 | | Co Leeds | 5:55.31 |
| 5 | 18 | Reuben BARKER | 10 | | Co Leeds | 6:14.38 |
| 6 | 16 | Callum YOUNG | 10 | | Co Leeds | 6:20.00 |
| 7 | 14 | Zachary GAWRONEK | 11 | | Warrington W | 6:20.30 |
| 8 | 12 | David MCINTOSH | 9 | | Co Leeds | 6:28.11 |
| 9 | 10 | Noah BEDFORD COLLINS | 10 | | Co Leeds | 6:35.00 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 21 | Yin Ho Adrian CHAN | 11 | | Co Leeds | 5:53.33 |
| 1 | 23 | Jacob CAWOOD | 11 | | Co Leeds | 5:51.92 |
| 2 | 25 | Zac PHILLIPS | 11 | | Co Leeds | 5:47.09 |
| 3 | 27 | Finn EASINGWOOD | 12 | | Co Leeds | 5:38.60 |
| 4 | 29 | Owen TEMPEST | 13 | S14 | Co Leeds | 5:32.45 |
| 5 | 28 | Samuel FORD | 11 | | Co Leeds | 5:37.70 |
| 6 | 26 | Myles RUDD | 14 | | Warrington W | 5:46.50 |
| 7 | 24 | Theo SIRA | 11 | | Co Leeds | 5:51.49 |
| 8 | 22 | Finley SMITH | 10 | | Co Leeds | 5:52.97 |
| 9 | 20 | Alfred WHITELL | 11 | | Co Manch Aq | 5:54.18 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 31 | Tom MCLEAN | 12 | | South Tyne | 5:27.79 |
| 1 | 33 | Harrison WAKE | 13 | | Co Leeds | 5:26.43 |
| 2 | 35 | Sebastian BAIRD | 12 | | South Tyne | 5:24.63 |
| 3 | 37 | Leo CLEGG | 13 | | Conwy | 5:16.60 |
| 4 | 39 | Alfie DENT | 15 | | South Tyne | 5:14.80 |
| 5 | 38 | David GRIGORE | 12 | | Co Leeds | 5:15.44 |
| 6 | 36 | Hisoka O'BRIEN | 13 | | Warrington W | 5:17.20 |
| 7 | 34 | Abdullah MOKHLISSE | 15 | | Chapeltown | 5:26.40 |
| 8 | 32 | Liam LI | 10 | | Co Leeds | 5:27.44 |
| 9 | 30 | Thomas SEDDON | 13 | | Aquabears | 5:32.30 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 41 | Hogan LAM | 13 | | Co Leeds | 5:07.60 |
| 1 | 43 | Callum FOZARD | 14 | | Co Leeds | 5:05.46 |
| 2 | 45 | Henry PATTERSON | 11 | | Co Leeds | 5:01.65 |
| 3 | 47 | Matthew MACKAY | 17 | | Co Manch Aq | 5:00.80 |
| 4 | 49 | Jack MCCOY | 15 | | Warrington W | 4:59.80 |
| 5 | 48 | Oliver BARKER | 12 | | Co Leeds | 5:00.71 |
| 6 | 46 | Harvey HOWARD | 16 | | Warrington W | 5:01.40 |
| 7 | 44 | Harley GILL | 13 | | Co Leeds | 5:03.50 |
| 8 | 42 | Dylan MEYERS | 14 | | Aquabears | 5:07.50 |
| 9 | 40 | Harry DIXON | 11 | | Co Leeds | 5:13.03 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 0 | 51 | Oliwier ZAJAC | 15 | | Warrington W | 4:55.48 |
| 1 | 53 | Benjamin CLARK | 13 | | Co Leeds | 4:54.27 |
| 2 | 55 | Oscar HUSSEY | 13 | | Co Leeds | 4:50.74 |
| 3 | 57 | Enzo SHILAND-GRIFFITHS | 14 | | Caernarfon | 4:44.10 |
| 4 | 59 | Oliver BROWN | 16 | | South Tyne | 4:30.90 |
| 5 | 58 | Jackson CLARKE | 15 | | Co Leeds | 4:40.44 |
| 6 | 56 | Now PARRY | 15 | | Caernarfon | 4:47.40 |
| 7 | 54 | Jack WADE | 12 | | Co Leeds | 4:51.20 |
| 8 | 52 | Cameron MILLER | 12 | | N Ayrshire | 4:54.80 |
| 9 | 50 | Zachary WHITTAKER | 12 | | Co Leeds | 4:56.55 |