HNLMS O 12

O 12 was a O 12-class submarine of the Royal Netherlands Navy. Built at Koninklijke Maatschappij De Schelde in Vlissingen, it was launched in 1930 but was unable to take part in military action during World War II. After being scuttled by the Dutch Navy, it was raised by the German Navy and taken into service as U-D2, and then scuttled again.

Before World War II
In 1935, O 12, with the O 13, O 15, Hertog Hendrik, Van Ghent, Kortenaer and Z 5, sailed the North Sea making stops at Göteborg and Oslo. Two years later, O 12 sailed with sister ship the O 14 to Surinam and Curaçao.

During World War II
During the German attack on the Netherlands in 1940, O 12 was in the naval wharf of Willemsoord, Den Helder for periodic maintenance. Unable to make the trip across the North Sea to England, the ship was scuttled.

The German occupying forces had O 12 raised and sent it to the Wilton-Fijenoord wharf in Rotterdam for repairs. On January 30, 1943, it was taken into service by the German Navy, the Kriegsmarine, as the U-D2. On July 6, 1944, it was taken out of service and moved to Kiel, where it was scuttled in the harbor just before the end of the war. Afterwards, O 12 was raised and demolished.