Plan Z
"U-30" was ordered by the "Kriegsmarine" on 1 April 1935 (as part of Plan Z and in violation of the Treaty of Versailles). Her keel was laid down on 24 January 1936 by AG Weser, Bremen as yard number 911. She was launched on 4 August and formally commissioned into the" Kriegsmarine" on 8 October under the command of "Kapitänleutnant" ("Kptlt.") Hans Cohausz.