|Shipyard||Blohm & Voss, Hamburg (Werk 302)|
|Ordered||27 May 1916|
|Launched||26 May 1918|
|Commissioned||4 Sep 1918|
26 Nov 1918 - Surrendered to Japan. In japanese service as the O1 1920-21.
Dismantled at Yokosuka Navy Yard between January and March 1921. Between March 1924 and January 1925 she was used as a floating jetty at the Kure Submarine School. In 1925 she was rebuilt at Yokosuka as testbed for submarine salvage operations carried out by the tender ASAHI. On 19 Aug 1931 U 125 was re-commissioned as Auxiliary Vessel No. 2900 and used until 1935..
There was another U 125 in World War Two
That boat was launched from its shipyard on 10 Dec 1940 and commissioned into the Kriegsmarine on 3 Mar 1941. Take a look at U 125 from WWII.