| Under-17 Women 300 Metres |
| 39.61 | Shona Richards | Epsom & Ewell Harriers | Birmingham | 26/02/2012 |
| 39.53 | Arabella Wilson | Winchester & District AC | Sheffield | 13/02/2022 |
| 39.21 | Holly Ryan | Shaftesbury Barnet Harriers | Sheffield | 09/02/2025 |
| 39.17 | Holly Ryan | Shaftesbury Barnet Harriers | Lee Valley | 21/12/2025 |
| KEY |
| | mx Performance achieved in mixed sex race | |
| NOTE. A 3-character code between the club and the venue indicates that the athlete was not eligible to represent GB at the time of the performance but did have a Surrey County qualification. |
