EVENT 303 Mens Open 400m IM - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 3 | 1 | Alexander Carroll | 99 | Co Coventry | 4:39.61 |
| 4 | 3 | Max Murphy | 00 | Co Milton K | 4:39.05 |
| 5 | 2 | Alfie Collins | 00 | Hillingdon | 4:39.34 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 1 | 5 | Oliver Kincart | 98 | Portsmouth N | 4:38.71 |
| 2 | 7 | Luke Robins | 99 | Millfield | 4:38.33 |
| 3 | 9 | Thomas Dean | 00 | Maidenhead | 4:36.96 |
| 4 | 11 | Tom Derbyshire | 98 | Royal Wolv | 4:36.60 |
| 5 | 10 | Zak Logue | 98 | Co Sund'land | 4:36.75 |
| 6 | 8 | George Clough | 99 | Warrender Ba | 4:38.10 |
| 7 | 6 | Cameron Croot | 99 | Swansea Aq | 4:38.53 |
| 8 | 4 | Kieran Bird | 99 | Bicester | 4:38.87 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 1 | 13 | Max Jameson | 00 | Thanet Swim | 4:36.12 |
| 2 | 15 | Matthew George | 00 | Co Salford | 4:35.68 |
| 3 | 17 | Tony-Joe Trett Oliver | 99 | Mt Kelly | 4:34.68 |
| 4 | 19 | Hayden Griffiths | 97 | Ellesmere Co | 4:33.91 |
| 5 | 18 | Ryan Brown | 98 | Co Glasgow | 4:34.31 |
| 6 | 16 | Alastair Miley | 94 | Garioch | 4:34.77 |
| 7 | 14 | Nathan Wells | 98 | West Norfolk | 4:35.75 |
| 8 | 12 | Ashley Hogg | 98 | Co Manch Aq | 4:36.27 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 1 | 21 | Jamie O'Connor | 99 | Thanet Swim | 4:32.47 |
| 2 | 23 | Brodie Williams | 99 | Millfield | 4:32.40 |
| 3 | 25 | Rubens King | 97 | Guildford Ct | 4:31.94 |
| 4 | 27 | John Britton | 95 | Ealing | 4:31.16 |
| 5 | 26 | Luke Davies | 97 | Co Birm'ham | 4:31.67 |
| 6 | 24 | Ben Evans | 97 | Thanet Swim | 4:32.17 |
| 7 | 22 | Luke Thomas | 97 | Co Oxford | 4:32.43 |
| 8 | 20 | Craig Munden | 97 | Loughboro Un | 4:32.63 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 1 | 30 | Jacob Greenow | 99 | TauntonDeane | 4:29.30 |
| 2 | 34 | Joe Litchfield | 98 | Donc Dartes | 4:25.26 |
| 3 | 38 | Xavier Mohammed | 90 | Co Cardiff | 4:21.22 |
| 4 | 42 | Roberto Pavoni | 91 | Loughboro Un | 4:13.81 |
| 5 | 40 | Lewis Smith | 88 | UniOfStirl | 4:18.24 |
| 6 | 36 | Fraser Minnican | 95 | Loughboro Un | 4:23.88 |
| 7 | 32 | Fabian Whitbread | 92 | Co Oxford | 4:27.69 |
| 8 | 28 | Callum Lawrie | 98 | F.I.R.S.T. | 4:30.47 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | YoB | Club/Country | Time |
| 1 | 31 | Alex Dunk | 95 | Prescot | 4:27.71 |
| 2 | 35 | Thomas Paine | 94 | Co Manch Aq | 4:24.87 |
| 3 | 39 | Matthew Johnson | 95 | Bath Univ | 4:18.54 |
| 4 | 43 | Daniel Wallace | 93 | Warrender Ba | 4:12.78 |
| 5 | 41 | Max Litchfield | 95 | Co Sheffield | 4:15.63 |
| 6 | 37 | Mark Szaranek | 95 | Edinburgh Un | 4:21.45 |
| 7 | 33 | Tristan Slater | 93 | Millfield | 4:25.94 |
| 8 | 29 | Nathan Hughes | 00 | Hatfield | 4:29.67 |