Poseidon has been the name of a number of ships, both real and in fiction.
Real ships
- SS Poseidon was 1968–1969 the name of a steam cargo ship built in 1941 for the British Government and originally named Empire Ballard.
- BN Poseidon was 1951–1959 the name of a coastal tanker launched in 1942 as Empire Faun
- ST Poseidon was 1973–1976 the name of a steam tug built in 1941 for the British Government and originally named Empire Fir.
- HMS Poseidon was a Royal Navy Parthian-class submarine, launched in 1929 and sunk in 1931.
- USS Poseidon (ARL-12) was a United States Navy Achelous-class repair ship, built in 1944 and sold off in 1961.
- Greek submarine Poseidon (S-78), a Gato-class submarine
- Swedish Coast Guard vessel KBV 001 Poseidon (IMO 9380441)
In fiction
- USS Poseidon, a US Navy attack submarine in the 2005 film Phantom Below.
SS Poseidon A luxury liner in the Poseidon adventure 1972
See also
- Poseidon-class submarine, a Greek submarine class
- Poseidon (disambiguation)