The Royal Australian Navy served in the Mediterranean in both world wars. In May 1917, Australian destroyers were sent to the Mediterranean for anti-submarine work. From October 1917, the flotilla was based at Brindisi, Italy supporting the Otranto Barrage blocking the passage of Austro-Hungarian submarines to and from the Adriatic. In 1918, HMAS Huon, Parramatta and Yarra used kite balloons in the search for enemy submarines. On 2 October 1918, HMAS Swan and Warrego covered the bombardment of the submarine base at Durazzo, Albania. The following month, after Turkey had signed an armistice, the RAN patrolled the Black Sea with HMAS Swan visiting the head of the Sea of Azov to report on conditions.
In the Second World War, naval activity in the Mediterranean Sea was a furious struggle by both sides to keep their armies supplied with the materials and reinforcements they needed. When Italy declared war in June 1940, HMAS Sydney, and five Australian destroyers were serving with the British Mediterranean Fleet, based at Alexandria, Egypt. On 28 June, the British 7th Cruiser Squadron, which included the Sydney intercepted three Italian destroyers carrying out escort duties for a convoy en route to Libya, sinking the Espero, the first Italian warship destroyed in the war. On 19 July 1940, the Sydney came to the rescue of four British destroyers on an anti-submarine patrol as they were being engaged by two Italian cruisers. After a running battle that lasted for an hour, HMAS Sydney sank the Bartolomeo Colleoni and inflicted considerable damage on the other Italian vessel, Giovanni Della Bande Nere.
HMAS Sydney left the Mediterranean for Australia in January 1941 and was replaced by HMAS Perth, which saw action at the Battle of Cape Matapan in March 1941. Perth and some of the Australian destroyers were involved with the movement of troops to Greece and in the evacuation of Greece and Crete in April and May 1941. Australian destroyers made of total of 139 runs in and out of besieged Tobruk in 1941. Two Australian ships HMAS Waterhen and HMAS Parramatta were lost doing this vital work. Between July and December 1941, the remaining Australian ships in the Mediterranean sailed for home. They were in need of extensive refits, and after the bombing of Pearl Harbour on 7 December they sailed to reinforce the Australian station.
The last Australian troops left for Australia in early 1943 but RAAF squadrons remained in the Middle East and at the end of the war were in Italy. Hundreds of Australians served in RAF squadrons in both the Mediterranean and Balkan theatres until the end of the war.