The Royal Navy of the Kingdom of Erusea, formerly known as the Federal Navy during the period of military rule (1982–2005), was the naval warfare branch of the Erusean military and one of the most prestigious naval forces in the world. For most of its existence, the Erusean state boasted a large fleet of warships that could project the country's power all over the world. The Navy was expanded even further under the military junta of the Federal Republic following the 1982 Erusian coup d'etat. It took considerable losses during the Second Usean Continental War and was downsized considerably by the new ISAF-backed government, which restored the monarchy.
Ships of the Royal Navy used the title ERS ("Erusian Royal Ship") for much of its history, and the title EFS ("Erusian Federation Ship") during the junta.