25/09/1921+
Restarted
20/12/1924

15/02/1923
+
Relaunched
25/09/1926

HomeBase: Sasebo ND;
25/09/1926-15/11/1934=Sasebo ND;
15/11/1934-15/12/1938=Sub.Div.25; Sasebo ND;
15/12/1938-09/02/1942=Sub.Div.25; 4th Reserve; Sasebo ND;
09/02/1942-14/07/1942=Kure ND;
14/07/1942-15/01/1943=Yokosuka ND;
15/01/1943-31/01/1944=Kure ND;
31/01/1944-25/05/1945= 4th Reserve; Kure ND;

(A)CEO:Lt.Ikeda Susumu [38]=20/04/1923-12/05/1923; ???
CO:Lt.Cdr.Kamibayashi Kiyoshi [34]=//1923-21/08/1923; KIAcc;
CEO: ? =25/09/1926-05/11/1926;
CEO:Lt.Cdr.Yoshitomi Setsuzo [39]=05/11/1926-10/05/1927;
CO:Lt.Cdr.Yoshitomi Setsuzo [39]=10/05/1927-16/05/1928;
CO:Lt.Cdr.Nakajima Chihiro [43]=16/05/1928-01/11/1929;
CO:Lt.Cdr.Abe Nobuo [42]=01/11/1929-01/12/1930;
CO:Lt.Cdr.Teraoka Masao [46]=01/12/1930-05/10/1932;
CO:Lt.Tsuzuki Noboru [48]=05/10/1932-20/03/1934;;
(+)CO:Lt.Emi Tetsushiro [50]=20/03/1934-01/11/1934;
(+)CO:Lt.Nakagawa Hajime [50]=01/11/1934-15/12/1934;
CO:
(+)CO:Cdr.Yoshimura Iwao [51]=15/01/1942-31/01/1942;
CO:Lt.Cdr.Shimose Kichiro [58]=31/01/1942-30/06/1942;
CO:Lt.Cdr.Hashimoto Mochitsura [59]= /07/1942- /02/1943;
CO:CO:Lt.Cdr.Nakamura Motoo [62]=16/03/1943-12/06/1943;
CO:Lt.Cdr.Kobayashi Hinomoto [0]=12/06/1943-01/07/1943;
CO:Lt.Cdr.Kamimoto Nobuo [56]=01/07/1943-31/01/1944;
CO:

10/05/1927 Renumbered RO-31;
21/08/1923 Sunk, diving trials off Kobe before completion;
No Survivors; 88KIAcc;(46 Navy personel + 42 Shipyard employees)
24/10/1924 Salvaged;
20/12/1924 Restarted on slips;
25/09/1926 Relaunched + Returned to Service;
10/05/1927 Completed;
25/05/1945 Removed from Navy List;
02/09/1945 Surrendered=Sasebo;
05/04/1946 Scuttled off Sasebo;