Daniel Andrews, of Rhyl Youth Boxing Club, sought planning permission to convert a vacant workshop and auction room, at 82 Marsh Road (where the club is also based).
Denbighshire County Council approved his application on Wednesday (June 17).
It is proposed that the gym will be open from 9am to 9pm from Monday to Friday, 9am to 11pm on Saturdays, and 9am until 5pm on Sundays and bank holidays.
The council granted planning permission, but with numerous conditions attached.
These include that the development starts within the next five years, that it is carried out “in strict accordance” with the details in the application, and that a biodiversity enhancement scheme is first submitted and approved.
This must include provisions for roosting bats and nesting birds, including the number, location and specification of those features.