The Oyashio class is a series of Japanese diesel-electric attack submarines operated by the JMSDF.

The submarines are larger than the earlier Harushio class, to provide space for a flank sonar array.

Oyashio, Michishio, and Kuroshio share their names with World War II destroyers.

On February 1, 2018, the Ministry of Defence's Maritime Staff Office revealed that seven of the service's 82-metre (269 ft 0 in) Oyashio-class submarines, which have a surface displacement of 2,800 tonnes, have already completed service-life extension work to date.

The seven boats received extensive refits during their second and third maintenance cycles, which have been planned to bring the vessels to "almost the same level of that of the latest model Sōryū-class submarine, while extending their service lives.