HMS Otranto was an armed merchant cruiser requisitioned by the British Admiralty when World War I began in 1914. Built before the war for the UK–Australia run as SS Otranto, she was primarily used in the war to search for German commerce raiders. She played small roles in the Battle of Coronel in November 1914 when the German East Asia Squadron destroyed the British squadron searching for it and in the Battle of the Falkland Islands the following month when a British squadron annihilated the Germans in turn.

The Battle of Coronel was a First World War Imperial German Navy victory over the Royal Navy on 1 November 1914, off the coast of central Chile near the city of Coronel. The East Asia Squadron of the Imperial German Navy led by Vice-Admiral Graf Maximilian von Spee met and overpowered a British squadron commanded by Rear-Admiral Sir Christopher Cradock.