EVENT 301 Mixed 09 Yrs/Over 400m Freestyle - Heats
| Heat Number - 1 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 1 | Tilly WASKETT-BOOTH | 9 | Grantham | |
| 3 | 2 | Olivia CHARITY | 13 | Grantham | 7:01.60 |
| 4 | 3 | Hollie-Ann CROOK | 11 | Grantham | 6:50.26 |
| Heat Number - 2 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 2 | 4 | Hannah EXLEY | 11 | Grantham | 6:45.00 |
| 3 | 5 | Lucia CORTON | 10 | Grantham | 6:45.00 |
| 4 | 6 | Esmé EVANS | 11 | Grantham | 6:45.00 |
| 5 | 7 | Emily CLAYTON | 11 | Grantham | 6:45.00 |
| Heat Number - 3 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 8 | Abigail TAYLOR | 11 | Grantham | 6:40.00 |
| 2 | 9 | Francesca WESTON | 10 | Grantham | 6:40.00 |
| 3 | 10 | William PENNOCK | 11 | Grantham | 6:35.00 |
| 4 | 11 | Matilda MCDONNELL | 12 | Grantham | 6:30.56 |
| 5 | 12 | Madeline SURTEES | 13 | Grantham | 6:24.36 |
| 6 | 13 | Louis WRIGHT | 12 | Grantham | 6:20.00 |
| Heat Number - 4 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 14 | Lucy ABBOTT | 13 | Grantham | 6:15.67 |
| 2 | 15 | Freddie HIRST | 11 | Grantham | 6:11.75 |
| 3 | 16 | Ella KHAMA | 11 | Grantham | 6:10.00 |
| 4 | 17 | Ava-Grace GREGORY | 13 | Grantham | 6:09.84 |
| 5 | 18 | Markas PARAPIJONAVICIU | 12 | Grantham | 6:07.26 |
| 6 | 19 | Octavia SHEARN | 13 | Grantham | 6:00.00 |
| Heat Number - 5 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 20 | Derrin BROCKLEBANK | 11 | Grantham | 5:57.22 |
| 2 | 21 | Isabelle CLAYTON | 13 | Grantham | 5:48.08 |
| 3 | 22 | Arthur BREARLEY-NEWSOM | 14 | Grantham | 5:47.84 |
| 4 | 23 | Mia PARAPIJONAVICIUTE | 16 | Grantham | 5:43.68 |
| 5 | 24 | Leo BARNETT | 13 | Grantham | 5:42.19 |
| 6 | 25 | Thomas HILLSON | 12 | Grantham | 5:36.85 |
| Heat Number - 6 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 26 | Toby EDMONDSON | 11 | Grantham | 5:36.01 |
| 2 | 27 | Elisabeth KINNEAR | 15 | Grantham | 5:33.49 |
| 3 | 28 | Jimmin BAO | 12 | Grantham | 5:32.33 |
| 4 | 29 | Grace HOWITT | 16 | Grantham | 5:31.30 |
| 5 | 30 | Joshua KIM | 13 | Grantham | 5:25.66 |
| 6 | 31 | George LEONARD | 13 | Grantham | 5:19.82 |
| Heat Number - 7 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 32 | Isobel ALLSOP | 15 | Grantham | 5:19.45 |
| 2 | 33 | Lizzy LERESCHE HANDS | 14 | Grantham | 5:12.00 |
| 3 | 34 | Amy TAYLOR | 14 | Grantham | 5:06.62 |
| 4 | 35 | Ellena HOWITT | 14 | Grantham | 5:04.65 |
| 5 | 36 | Isla GRAY | 15 | Grantham | 4:48.18 |
| 6 | 37 | Elena ALDENHOFF-KELLY | 17 | Grantham | 4:47.83 |
| Heat Number - 8 |
| Lane | Comp.No. | Name | AaD | Club | Time |
| 1 | 39 | Chloe HOPKINSON | 20 | Grantham | 4:37.43 |
| 2 | 41 | Ben CARLYLE | 15 | Grantham | 4:30.79 |
| 3 | 43 | Zach HOPKINSON | 16 | Grantham | 4:21.37 |
| 4 | 42 | Jacob FISH | 16 | Grantham | 4:29.86 |
| 5 | 40 | Grace TURNER | 18 | Grantham | 4:30.91 |
| 6 | 38 | Lucy WILLATTS | 14 | Grantham | 4:47.63 |