Garden Island has supported naval activities since 1788 with the role and utilisation of the island varying over the years. Originally the small island of 4.6 hectares was literally used as a garden bed to produce food for the ship's company. By 1946 land had been reclaimed between Potts Point and Garden Island, expanding the Garden Island site to 27 hectares.
The two main users of Garden Island are the Navy and Thales Australia. Garden Island is the main base for the Navy Fleet on Australia's East Coast. Thales Australia manages and operates a graving dock (dry dock), a floating dock and a range of ship engineering and maintenance facilities at Garden Island. Garden Island is part of the rich fabric of the Port of Sydney and one element fulfilling the stated desire of the State Government to have a working harbour.