The Royal Australian Navy's largest fleet base, Fleet Base West, also called HMAS Stirling,[3][full citation needed] is on the shores of Careening Bay, on the southeastern section of Garden Island, facing Cockburn Sound.

[4][full citation needed] The entirety of Garden Island is included on the Commonwealth Heritage List for its natural values.

Stirling returned to the area in 1829, claiming Garden Island as part of his grant of 40,469 hectares (100,000 acres), plus any livestock remaining from the previous visit.

Two US-supplied mobile Canon de 155 mm guns on Panama mount were installed to protect Garden Island, Cockburn Sound and the Challenger Passage.

During World War II, Careening Bay Camp became a major training base for the secretive Services Reconnaissance Department (SRD), also commonly referred to as Z Special Unit.

SRD parties staging out of Careening Bay Camp were sent on clandestine missions into Japanese-occupied territory.

In 1966, a feasibility study began into establishment of a naval support facility on the island, which was endorsed by the Australian Government in 1969.

The facility was completed in 1978, and HMAS Stirling was formally commissioned as a unit of the Royal Australian Navy in the same year.

A designated access road to the base, the Garden Island Highway, was also proposed and a small section constructed but never completed and eventually cancelled in 1984.