This wreck is located between Alava Pier and the North-East end of the Subic Bay Airport Runway, right next to the shipping lanes about 150 meters North of USS New York. The Seian Maru was bombed and sunk by American airplanes at the end of 1944. She ran aground just outside of Subic Bay on the 17th of November 1944 but was re-floated and escorted back into Subic Bay by a Submarine Chaser (CH-36). On the 19th of November 1944 both vessels were sunk in an air raid. CH-36 is not a know dive site.

It’s hard to say much about the history of the Seian Maru due to the lack of useful records. Japanese documentation show that there were at least three ships in use (and sunk) during the war with the name “Seian Maru”. In addition to that, most records created during wartimes are often inaccurate. The American Naval pilots that sank this vessel identified her as a merchant tanker, something that was later on backed up by Japanese records showing her as having been modulated into a tanker and later restored back into a cargo ship.

The wreck is today located at a depth of between 16-32 meters. The vessel is estimated to have weighed about 3,700 t., and is 106 meters (350 ft.) long and over 15 meters (50 ft.) wide. The Seian Maru was badly damaged in the American bombing raid back in 1944 and with natures work its today, almost 70 years later, very hard to visualize parts of its superstructure, such as its stern and bow. However, once you reach the wreck site you will be able to go over its ruined structures accompanied by a large variety of coral fish. Due to the depth of this site we recommend you to be at least an Advance Open Water Diver before conducting any diving here.

We shouldn’t forget the fact that this site is a war grave, which in our opinion should not be disturbed. As a result we very rarely dive on this wreck.

The Seian Maru dive site is occasionally closed for recreational diving by the authorities. Please contact us for more information about this wreck site.



  • Latitude: 14° 48.585′ N
  • Longitude: 120° 16.919′ E
  • Copy and paste in Google Maps to view the location; 14° 48.585′ N, 120° 16.919′ E  (Google Maps)