AE1 was an E Class Submarine assigned to the capture of the German Pacific colonies at the outbreak of the First World War. She was commissioned at Portsmouth on 22 May 1913 and reached Sydney from England, with her sister AE2, on 24 May 1914.
AE1 had a crew of 35 and was commanded by Lieutenant Commander Thomas Besant. On 11 September 1914 she arrived off Rabaul, New Guinea, as part of force of 6 naval ships, 2 submarines, a store-ship, 3 colliers and the Berrima.
Three days later — a day after the official German surrender of the colony of New Guinea — AE1 left Rabaul harbour to patrol Cape Gazelle. She exchanged signals with the HMAS Parramatta between 8 am and 2.30pm and was last seen at 3.20pm. Parramatta believed that she must have steamed back into harbour without informing her, however a later search for the submarine found no trace.
The loss of AE1 with her entire crew was the RAN’s first major tragedy. The Farmer and Settler reported on Monday 21 September 1914:
“When, twelve months ago, the first ships of Australia's little navy arrived on our coasts, there were few that would have listened to a prophecy of a world war in 1914… only, four months ago, our two submarines arrived, after the unparalleled feat of steaming half round the globe, there were few that could have imagined themselves hearing so soon afterwards the news of the loss of one of those baby warships, on active service, carrying thirty-five brave men to an ocean grave.”
The fate of AE1 and her crew has never been discovered. It is probable that she was caught on a coral reef and sank.