There are a total of 11 boats in the class - the last boat was commissioned in 2008. Oyashio, Michishio, and Kuroshio share their names with World War IIdestroyers. Takashio shares a name with a ship from the third set of Yūgumo-class destroyers, of which none were built.
The first two boats, Oyashio and Michishio along with the Makishio, have since been converted to training platforms.
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.[1]
^ ab"「おやしお」25年の歴史に幕 「まきしお」が練習潜水艦に(2023年3月17日)" ["Oyashio" comes to an end after 25 years of history; "Makishio" becomes training submarine (March 17, 2023)]. Asagumo News (in Japanese). 9 May 2023. Archived from the original on 9 May 2023. Retrieved 2 January 2025.
^Saunders, Stephen (2004). Jane's Fighting Ships 2004-2005. Jane's Information Group. p. 384. ISBN0-7106-2623-1.