EVENT 209 Open/Male 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 2 | 1 | Jacob Dessoy | 16 | S8 | Runnymede | 6:37.35 |
| 3 | 3 | Lucas Day | 15 | | Rochford | 4:27.82 |
| 4 | 5 | Oliver Fuller | 14 | | Co Cambridge | 4:24.48 |
| 5 | 4 | Jake Lloyd | 29 | | Bishop Stort | 4:25.60 |
| 6 | 2 | Corey Hare | 18 | S14 | teamipswich | 4:39.90 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 7 | Frank Lamb | 15 | | Co Peterboro | 4:22.62 |
| 2 | 9 | George Carter | 16 | | Co Cambridge | 4:22.37 |
| 3 | 11 | Dylan Davenport | 15 | | Bishop Stort | 4:21.54 |
| 4 | 13 | Jacob Bacon | 14 | | Co Peterboro | 4:18.80 |
| 5 | 12 | Kian Lee | 16 | | Co Peterboro | 4:19.80 |
| 6 | 10 | Thomas Spelman | 17 | | Stowmarket | 4:22.10 |
| 7 | 8 | Ashton Blake | 15 | | Basildon Ph | 4:22.54 |
| 8 | 6 | Cameron Jones | 18 | | Bedford SS | 4:24.45 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Cat | Club | Time |
| 1 | 15 | Oscar Hunter | 15 | | Norwich Swan | 4:18.50 |
| 2 | 17 | Robert Fenner | 16 | | Basildon Ph | 4:15.56 |
| 3 | 19 | Ryan Wall | 17 | | Co Cambridge | 4:06.04 |
| 4 | 21 | Alexander Volkovoy | 19 | | Co Cambridge | 3:52.03 |
| 5 | 20 | Daniel Belsey | 16 | | Hatfield | 4:01.08 |
| 6 | 18 | Adam O'Neal | 16 | | Bedford SS | 4:10.02 |
| 7 | 16 | Luke Martell | 18 | | Watford SC | 4:18.50 |
| 8 | 14 | B Macdonald-Williams | 16 | | Bishop Stort | 4:18.65 |