Real ships

• SS Poseidon
  SS Empire Ballad
  Empire Ballad was a 6,640 ton cargo ship which was built by Bartram & Sons Ltd, Sunderland in 1941 for the Ministry of War Transport . She was sold to Alexander Shipping Co Ltd in 1946 and renamed Bibury. In 1951 she was sold to Halcyon Lijn NV, Rotterdam, Netherlands and renamed Stad Maassluis...
  
   was 1968-1969 the name of a steam cargo ship built in 1941 for the British Government and originally named Empire Ballard.
• 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
  Royal Navy
  The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
  
   Parthian-class
  Parthian class submarine
  The Parthian class submarine or P class was a class of six submarines built for the Royal Navy in the late 1920s. They were designed as long-range patrol submarines for the Far East. These ships were almost identical to the Odin class, the only difference being a different bow...
  
   submarine
  Submarine
  A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
  
  , launched in 1929 and sunk in 1931.
• USS Poseidon
  USS Poseidon (ARL-12)
  The USS Poseidon was one of 39 Achelous-class landing craft repair ships built for the United States Navy during World War II. Named for Poseidon , she was the only ship U.S. Naval vessel to bear the name....
  
   was a US Navy Achelous class repair ship
  Achelous class repair ship
  The Achelous class repair ship was a class of ship built by the US Navy during World War II.As the US gained experience in amphibious operations, it was realized that some sort of mobile repair facility would be useful for repairing the damage that frequently occurred to smaller vessels such as...
  
  , built in 1944 and sold off in 1961.

In fiction

• Poseidon, the subject of the 1969 novel The Poseidon Adventure as well as the films based on that novel: The Poseidon Adventure (1972), Beyond the Poseidon Adventure
  Beyond the Poseidon Adventure
  Beyond the Poseidon Adventure is a 1979 American disaster film, a sequel to the 1972 film The Poseidon Adventure. It was directed by Irwin Allen and starred Michael Caine and Sally Field...
  
   (1979), The Poseidon Adventure
  The Poseidon Adventure (2005 film)
  The Poseidon Adventure is a 2005 action and adventure film based on a novel by Paul Gallico. It is a remake of the 1972 film of the same name.-Plot:...
  
   (2005), and Poseidon
  Poseidon (film)
  Poseidon is a 2006 disaster film directed by Wolfgang Petersen, the third film adaptation of the novel The Poseidon Adventure written by Paul Gallico, and a loose remake of the 1972 film of the same name. It stars Kurt Russell, Josh Lucas and Richard Dreyfuss. It was directed by Wolfgang Petersen...
  
   (2006).
• USS Poseidon, a US Navy attack submarine in the 2005 film Phantom Below
  Phantom Below
  Phantom Below is the first film released by Hawaii-based studio Pacific Films. Its world premiere was at the Hawaii International Film Festival on March 31, 2005...
  
  .