The island was originally a rocky outcrop, but in 1931-2 it was increased in size over seven times by land reclamation, and reshaped into the general plan form of a ship.

[3] In 1879, Snapper Island was declared a public recreation reserve by the NSW Legislative Assembly.

[1][3] In 1930, Len Forsythe leased the island from the Commonwealth Government in order to create a training depot for boys in nautical skills.

The British also used some of the facilities on Snapper Island as a social club for troops on leave.

Opened after 1966, the museum held thousands of pieces of memorabilia from Australia's naval history.