EVENT 301 Open/Male 10 /Over 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 1 | Thomas VERE | 11 | South Lincs | |
| 2 | 3 | Cameron JAMISON | 10 | Lincoln TSA | |
| 3 | 5 | Thomas HILLSON | 12 | Grantham | |
| 4 | 7 | Kai HILAROWICZ | 12 | Co Lincoln P | |
| 5 | 6 | Toby EDMONDSON | 11 | Grantham | |
| 6 | 4 | Derrin BROCKLEBANK | 11 | Grantham | |
| 7 | 2 | Damir IVANOVS | 10 | Boston | |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 9 | Oscar WOOD | 12 | Lincoln Vulc | |
| 2 | 12 | Dan PALMER | 12 | Co Lincoln P | |
| 3 | 14 | Cole COOPER | 13 | Co Lincoln P | |
| 4 | 16 | Finley WEST | 14 | Co Lincoln P | |
| 5 | 15 | Finley ROWDING | 14 | Co Lincoln P | |
| 6 | 13 | Oliver WILKINSON | 13 | Lincoln Vulc | |
| 7 | 10 | Henry WILLERTON | 12 | Skegness | |
| 8 | 8 | Jimmin BAO | 12 | Grantham | |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 18 | Robbie DUFF | 14 | Lincoln Vulc | |
| 2 | 20 | Henry MASON-SMITH | 14 | Louth | |
| 3 | 22 | James HUCKLE | 14 | Lincoln Vulc | |
| 4 | 24 | James CASH | 15 | Deepings | |
| 5 | 23 | Oliver JONES | 16 | Lincoln Vulc | |
| 6 | 21 | Riley HAMER | 15 | Co Lincoln P | |
| 7 | 19 | Kieran LUCY | 15 | South Lincs | |
| 8 | 17 | James THOMAS | 15 | Gainsborough | |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 26 | William VERE | 16 | South Lincs | |
| 2 | 28 | Zach HOPKINSON | 16 | Grantham | |
| 3 | 30 | William KITE | 16 | Louth | |
| 4 | 32 | Layton ANNISON-SNOWDEN | 16 | Louth | |
| 5 | 31 | Jacob FISH | 16 | Grantham | |
| 6 | 29 | Matthew TOMPKINSON | 16 | Louth | |
| 7 | 27 | Luke DAYBELL | 16 | Grantham | |
| 8 | 25 | Ben CARLYLE | 15 | Grantham | |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 34 | Daniel HEPPLESTONE | 15 | Co Lincoln P | |
| 2 | 36 | Morgan FARRAR | 16 | Co Lincoln P | |
| 3 | 38 | Jensen HYLTON | 17 | Co Lincoln P | |
| 4 | 40 | Joseph PARNELL | 18 | Co Lincoln P | |
| 5 | 39 | Joshua CLARKE | 17 | Grantham | |
| 6 | 37 | Alex SADLER | 18 | South Lincs | |
| 7 | 35 | Ryan NORTON | 18 | Boston | |
| 8 | 33 | Archie FRENCH | 16 | Lincoln Vulc | |