Kaibōkan (海防艦, "sea defence ship") or coastal defense ship is a type of naval ship used by the Imperial Japanese Navy during World War II for escort duty and coastal defense. The term escort ship is used by the United States Navy to describe this category of Japanese ships.[not in citation given]
These ships were the Japanese equivalent to Allied destroyer escorts and frigates, all three types of warships being built as a less expensive anti-submarine warfare alternative to fleet destroyers. Kaibōkan had few counterparts among Japan's Axis allies: the 10 Kriegsmarine escort ships of the F-class, and Amiral Murgescu of the Romanian Navy.
In the course of the war, the design was simplified and scaled down to permit larger numbers of vessels to be built more quickly.