SM U-123, a Type UE II submarine launched in 1918 and that served in World War I until surrendered on 22 November 1918; sunk on east coast of England on way to be broken up in 1921
During World War I, Germany also had this submarine with a similar name:
This article includes a list of ships with the same or similar names. If an internal link for a specific ship led you here, you may wish to change the link to point directly to the intended ship article, if one exists.