HMAS Sydney , named after the city of Sydney, New South Wales, is the third and final ship of the Hobart class air warfare destroyers used by the Royal Australian Navy (RAN).

The Álvaro de Bazán class, also known as the F100 class, is a class of Aegis combat system-equipped air defence frigates in service with the Spanish Navy. The vessels were built by Spanish shipbuilder Navantia in Ferrol, with the lead ship of the class named for Admiral Álvaro de Bazán.