Charlestown (meaning great cove) is a village and port on the south coast of Cornwall, England, United Kingdom, in the parish of St Austell Bay. It is situated approximately south east of St Austell town centre.
The port at Charlestown developed from what was in the late 18th century the fishing village of West Polmear. Whereas other areas within the conurbation of St Austell have seen much development during the 20th century, Charlestown has remained relatively unchanged within this expansion. There are deposits of china clay in the area. Particles of mica quartz in the sea near Charlestown give it a turquoise-blue colour. The same colour is imparted to flooded china clay quarries.