2023 - Monster Mountain Entry List - 125cc
| Name | Rider No | Sponsor | Team | Hometown | Manufacturer |
| Ashton Phillips | 6W | E.M.L.DRYWALL LTD\TS RACING | Staffordshire | GAS | |
| Tyler Jones | 7 | Hampshire | KTM | ||
| Levi Saunders | 10 | BLUE-3 (UK) LTD | BLUE 3 (UK) LTD | Kent | KTM |
| Freddie Gardiner | 14 | TEAM MATT GARDINER MX KTM | MATT GARDINER MX | Gloucestershire | KTM |
| Max Smith | 18 | REDLINE MOTORCYCLES | Northamptonshire | KTM | |
| Ollie Bubb | 44 | 3 FLO BLU CRU CRESCENT YAMAHA | 3 FLO BLU CRU CRESCENT YAMAHA | Gloucestershire | YAM |
| Reece Jones | 104 | SJP MOTO | South Yorkshire | KTM | |
| Braidy Tucker | 145 | JOOV 57TYRES \TUCKER & SONS BUILDING | Gwent | KTM | |
| George Corke | 181 | GRT | GRT | East Sussex | KTM |
| Lucy Barker | 310 | MATT GARDNER MX | Yorkshire | KTM | |
| Gus Mustoe | 361 | MATT GARDINER MX | MATT GARDINER MX | Gloucestershire | KTM |
| Wesley Mcgavin | 545 | NO 1 DAD | Leicestershire | KTM | |
| Max Corke | 616 | GRT Impact | GRT IMPACT | East Sussex | KTM |
| Jack Dando | 654 | Somerset | KTM | ||
| Jack Davis | 747 | APICO FACTORY RACING\DBC MOTORCYCLE | Hertfordshire | YAM |