HMAS AE1 (originally known as just AE1) was an E-class submarine of the Royal Australian Navy (RAN). She was the first submarine to serve in the RAN, and was lost at sea with all hands near what is now East New Britain, Papua New Guinea, on 14 September 1914, after less than seven months in service. Search missions attempting to locate the wreck began in 1976. The submarine was found during the 13th search mission near the Duke of York Islands in December 2017.