| Heat Number - 1 | |||||
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 2 | Louise HERRIOTT | 12 | South Lincs Competitive SC | 13:11.90 |
| 2 | 4 | Alfie GROUNSELL | 11 | Bassetlaw Swim Squad | 13:00.00 |
| 3 | 6 | Sophie BOLTON | 12 | South Lincs Competitive SC | 12:32.60 |
| 4 | 5 | Chelsea TODD | 13 | Lincoln Vulcans SC | 12:56.53 |
| 5 | 3 | Lucy JENKINSON | 12 | Deepings SC | 13:07.30 |
| 6 | 1 | Esme LUCAS | 9 | South Lincs Competitive SC | 16:43.60 |
| Heat Number - 2 | |||||
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 8 | Joshua BUTTERWORTH | 14 | Lincoln Vulcans SC | 11:50.00 |
| 2 | 10 | Isla STOCKLEY | 11 | Bassetlaw Swim Squad | 11:34.91 |
| 3 | 12 | Pela TIAN-WRIGHT | 13 | South Lincs Competitive SC | 11:27.30 |
| 4 | 11 | Rowan OSBORNE | 13 | Lincoln Vulcans SC | 11:30.00 |
| 5 | 9 | Morgan GRIFFIN | 13 | South Lincs Competitive SC | 11:43.00 |
| 6 | 7 | Iris Acacia LUCAS | 12 | South Lincs Competitive SC | 12:18.00 |
| Heat Number - 3 | |||||
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 14 | Iris FRENCH | 13 | Lincoln Vulcans SC | 11:26.29 |
| 2 | 16 | Reuben OWEN | 13 | South Lincs Competitive SC | 11:17.70 |
| 3 | 18 | Isla SCOTT | 13 | Lincoln Vulcans SC | 10:56.28 |
| 4 | 17 | Charlotte TURNER | 13 | Lincoln Vulcans SC | 11:11.19 |
| 5 | 15 | Maisie ASMAN | 13 | Lincoln Vulcans SC | 11:24.96 |
| 6 | 13 | Emily HUNT | 13 | Lincoln Vulcans SC | 11:26.88 |
| Heat Number - 4 | |||||
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 20 | Emily BRIGGS | 14 | South Lincs Competitive SC | 10:23.53 |
| 2 | 22 | Iona WATSON | 14 | Bassetlaw Swim Squad | 10:17.46 |
| 3 | 24 | Samuel POTTER | 14 | Bassetlaw Swim Squad | 9:48.76 |
| 4 | 23 | Evie LILLEY | 14 | Bassetlaw Swim Squad | 9:57.05 |
| 5 | 21 | Jessica HERRIOTT | 15 | South Lincs Competitive SC | 10:18.49 |
| 6 | 19 | Abigail BETTS | 13 | Bassetlaw Swim Squad | 10:38.15 |