On 5 January 1973, "Duchess" arrived at Williamstown Naval Dockyard for conversion into a training ship. The aft funnel was streamlined, and the remaining torpedo launcher, aft gun turret, and Squid mortar were all removed. This allowed for the installation of an extended aft superstructure, with classrooms, instructor offices, and additional accommodation for the embarked trainees. The former turret's loading bay was converted into library and study areas. A semi-enclosed charthouse was fitted above and behind the bridge for navigation training. The refit concluded on 14 August 1974, with "Duchess" replacing as the RAN's dedicated training vessel. From January 1975 to July 1976, "Duchess" operated on a sequence of training cruises, visiting ports along the eastern Australian coast, as well as New Zealand and the South Pacific. She was docked from July to October at Cockatoo Island Dockyard to combat hull corrosion, then resumed her training schedule. Her final training cruise ran during August and September 1977, after which, "Duchess" was replaced by .