The HMAS Sydney I was an Australian light cruiser commissioned into the Royal Australian Navy in 1913. It played a significant role during World War I, participating in various naval operations, including the Battle of Cocos in 1914, where it engaged the German cruiser SMS Emden. The ship was known for its speed and agility, making it an effective warship during its service. Unfortunately, HMAS Sydney I was sunk in 1912 after a collision with the HMAS Melbourne, leading to the loss of 645 crew members. Its legacy remains an important part of Australian naval history.