Maritime
- Arethusa class cruiser (disambiguation), two classes of Royal Navy cruiser
- Arethusa class cruiser (1912), eight light cruisers built in 1912–1914 that served in World War I
- Arethusa class cruiser (1934), four light cruisers built in 1934–1936 that served in World War II
- Aréthuse class submarine, a class of French submarine, in service 1958-1981
- HMS Arethusa, nine ships of the Royal Navy, 1759 to 1991
- USS Arethusa, three ships of the United States Navy 1864 to 1946
Read more about this topic: Arethusa