Fort Grey stands on the site of the old Rocquaine Castle, it was demolished in 1803 and was replaced by a strong battery protected by a semicircular wall ten feet thick. In 1804 the States of Guernsey built the martello tower within the walls and named it Fort Grey in honour of the Governor of the day.  The fort was manned by an officer and 30 men. 

During the Second World War, the fort became part of the German defence network on the west coast.

Fort Grey was restored by the islands Ancient Monuments Committee and opened as a shipwreck museum in 1975.

The museum is open daily from April - October.