Poster submarine Sōryū class

The Sōryū class, in service with the Japanese Navy since 2009, is a series of anaerobic submarines powered by Stirling engines built under license by Kawasaki Heavy Industries. These submarines use lead-acid batteries, replaced by lithium-ion batteries from the eleventh example, the JS Ōryū, which thus becomes the first submarine in the world equipped with this type of battery.

This class is an evolution of the Oyashio class, identifiable in particular by its St. Andrew's cross aft bars. In 2018, fourteen submarines were ordered, although only twelve were finally launched. Construction of the first submarine began in 2005, with a commissioning in 2009, and the last is expected in 2023. After the launch of the twelfth example, the Sōryū class evolved into the Taigei class, the first submarine of which entered service in 2022.

A model derived from this class had been proposed for the Australian Navy in competition with the Type 216 and the Shortfin Barracuda, but this option was abandoned in 2016 in favor of a French model. In 2017, the Indian Navy expressed an interest in submarines of similar design, but response times prevented Mitsubishi from proposing a variant of the Sōryū.