It runs for about 0.11 miles (0.18 km) between High Street to the north and South Street to the south.

St John's Place, which surrounds the ancient St John's Kirk, are the only junctions on the street, aside from a couple of vennels: Oliphants Vennel and Baxters Vennel, both of which connect St John Street to Watergate (which, along with Skinnergate, is one of the oldest streets in Perth).

[1] St John Street bounds St John's Kirk to the east; King Edward Street bounds it to the west.

Historic Scotland has twenty entries for listed buildings on St John Street.

[2] McEwens department store occupied 56 St John Street between 1868 and 2016.