Australia ordered its first submarines in 1910—two of the new British E class, displacing 810 tons submerged. These 176-foot long boats had a test depth of 100 feet and were armed with six torpedoes. A crew of 3 British officers and 32 Australian and British ratings manned the subs. Completed in early 1914, AE-1 and AE-2 (commanded by LCDR Henry H.G.D. Stoker, RN) left for Australia in February, arriving at Sydney in May. World War I started less than two months later. Their first wartime service was with a force sent to capture the German Pacific colonies. Unfortunately, AE- was lost with all hands in September during the invasion of New Britain.
AE-2 next was ordered to the Mediterranean. Leaving Australia on 31 December 1914, she joined Allied naval forces patrolling outside the Dardenelles in February 1915. The biggest and newest submarine on station, she was directed to penetrate the heavily fortified Dardenelles strait and enter the Sea of Marmora. The Turkish Navy was there and the capital, Constantinople, was at the far side of the sea. It could be a splendid "hunting ground" for naval forces.