The Marshal family, Earls of Pembroke to 1245, may have started construction of the walls, replacing an earthen rampart of the late 12th century, and they were completed by William de Valence, 1st Earl of Pembroke after Tenby was sacked in 1260 by Llewelyn ap Gruffydd.

Jasper Tudor, Duke of Bedford ordered the walls repaired and improved in 1457.

[2] At one time there were walls connecting the city to Tenby Castle, but they are no longer extant.

The walls are generally built of rubble stone with arrow loops and a crenellated parapet.

There is a short stretch west from Upper Frog Street along White Lion Street to the bastion at the corner of White Lion Street and South Parade and then the most intact portion runs south beside South Parade and St Florence Parade to the sea.