St Catherine's Island is a half-tide coastal islet, set immediately off Tenby. St Catherin's Chapel, first mentioned in documents of 1525, reportedly overhung the further end of the island in 1812. The chapel was demolished in 1868-1871 during the construction of St Catherine's fort (NPRN 268163), at which time three third century AD Roman coins were discovered. There are also twentieth century defensive features on the island (NPRN 270803).

J.Wiles, RCAHMW, 09.11.2004.