During exploration of the west coast of Africa, Sandwich Harbour was known as Port d’ Ilheo, meaning ‘point of the island’. It was explored by Diogo Cao on his journey in 1486. The harbour was also noted on a visit by the French Navy in 1733.
The name Sandwich Harbour first appears on a map published in 1791 by the British East India Company. It is believed that the map was drawn with the assistance of a sketch map provided by Samuel Enderby Jnr, who managed a whaling company.