On arrival, the six River-class ships were to undergo anti-submarine training, but were instead immediately deployed on convoy escort operations from Port Said to Malta. On 16 August, lookouts aboard "Parramatta" spotted the wake from a periscope. The destroyer sped to the area of the sighting, and dropped a depth charge on a submarine travelling just below the surface. After completing the convoy run, the Australian warships completed the training, and were assigned to patrols of the Adriatic. For this, "Parramatta" was fitted with an observation balloon. On 16 November 1917, "Parramatta" and several sister ships came to assist the Italian transport "Orione", whose stern had been destroyed by a torpedo. "Parramatta" towed the stricken ship towards the mainland, while "Warrego" and recovered survivors and "Yarra" chased the attacking submarine. Apart from this, the patrols were uneventful, and on 28 September 1918, "Parramatta" was refitted in Greece before joining Allied forces at Constantinople. During October 1918, following the surrender of Turkish forces, "Parramatta" accepted the surrender of a German admiral assigned to the area. The destroyer was then used for mail runs between Constantinople and Sevastopol, Russia, until December, when she sailed to Devonport, arriving on 14 January 1919.