| Heat Number - 1 | |||||
| Lane | Comp.No. | Name | YoB | Club | Time |
| 2 | 2 | Luca HALLAM | 12 | Grantham SC | 3:07.91 |
| 3 | 4 | Henry SEAGROATT | 11 | Louth Dolphins SC | 3:06.61 |
| 4 | 6 | Francesco MONACO | 12 | South Lincs Competitive SC | 2:58.58 |
| 5 | 5 | James HUCKLE | 11 | Lincoln Vulcans SC | 3:04.13 |
| 6 | 3 | Dominic MCLAUGHLIN | 11 | Louth Dolphins SC | 3:06.82 |
| 7 | 1 | Oscar DURANT | 11 | Grantham SC | 3:08.12 |
| Heat Number - 2 | |||||
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 8 | Oliver GARNER | 10 | City of Linc Pentaqua SC | 2:55.50 |
| 2 | 10 | Jacob HEGG | 10 | Lincoln Vulcans SC | 2:49.54 |
| 3 | 12 | James THOMAS | 10 | Gainsborough Dolphins SC | 2:47.03 |
| 4 | 14 | Oliver JONES | 09 | Lincoln Vulcans SC | 2:43.93 |
| 5 | 13 | Matthew TOMPKINSON | 09 | Louth Dolphins SC | 2:44.86 |
| 6 | 11 | James CASH | 10 | Deepings SC | 2:48.73 |
| 7 | 9 | Aaron SADLER | 10 | South Lincs Competitive SC | 2:53.31 |
| 8 | 7 | Jacob TURNER | 10 | Boston Amateur SC | 2:55.90 |
| Heat Number - 3 | |||||
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 16 | Jack HICKS | 09 | Lincoln Vulcans SC | 2:42.81 |
| 2 | 18 | Daniel HEPPLESTONE | 10 | Lincoln Vulcans SC | 2:40.48 |
| 3 | 20 | Zach HOPKINSON | 09 | Grantham SC | 2:36.71 |
| 4 | 22 | William TAYLOR | 08 | Louth Dolphins SC | 2:31.78 |
| 5 | 21 | Frank LAMB | 09 | South Lincs Competitive SC | 2:35.93 |
| 6 | 19 | Lewis TARVER | 08 | Deepings SC | 2:36.94 |
| 7 | 17 | Layton ANNISON-SNOWDEN | 09 | Louth Dolphins SC | 2:41.43 |
| 8 | 15 | Charlie BISBY | 11 | South Lincs Competitive SC | 2:43.70 |
| Heat Number - 4 | |||||
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 24 | Matteo MONACO | 09 | South Lincs Competitive SC | 2:30.70 |
| 2 | 26 | Evan NOORPURI | 07 | Lincoln Vulcans SC | 2:29.67 |
| 3 | 28 | Jacob FISH | 09 | Grantham SC | 2:27.09 |
| 4 | 30 | Christian O'MALLEY | 06 | Lincoln Vulcans SC | 2:25.68 |
| 5 | 29 | Harry KINGSTON | 04 | City of Linc Pentaqua SC | 2:25.81 |
| 6 | 27 | Jensen HYLTON | 08 | City of Linc Pentaqua SC | 2:28.10 |
| 7 | 25 | Leon BAILEY | 06 | Louth Dolphins SC | 2:29.92 |
| 8 | 23 | Kieran NG | 10 | South Lincs Competitive SC | 2:31.26 |
| Heat Number - 5 | |||||
| Lane | Comp.No. | Name | YoB | Club | Time |
| 1 | 32 | Finnley DANBY | 06 | Boston Amateur SC | 2:22.70 |
| 2 | 34 | Alex SADLER | 07 | South Lincs Competitive SC | 2:19.36 |
| 3 | 36 | Joseph PARNELL | 07 | City of Linc Pentaqua SC | 2:18.62 |
| 4 | 38 | Ethan RICHES | 03 | City of Linc Pentaqua SC | 2:06.50 |
| 5 | 37 | Thomas BRUCE | 06 | South Lincs Competitive SC | 2:17.20 |
| 6 | 35 | Oliver SORRELL | 07 | South Lincs Competitive SC | 2:19.35 |
| 7 | 33 | Owen HATHWAY | 06 | Grantham SC | 2:20.58 |
| 8 | 31 | Jack ZERAVICA | 08 | Grantham SC | 2:23.29 |