Hermann Leopold Ludwig Eugen Hans Heinz Bonatz[1] (18 August 1897 in Witzenhausen – 1981[1][2]) was a German naval officer during World War II.

He was most notable for being chief of B-Dienst (German: Beobachtungsdienst, literally: observation or monitoring service) until January 1944.

This division dealt with the interception and recording, decoding and analysis of the enemy - in particular British - radio communications.

From September 1932 to February 1934, he was acting as commander of the torpedo boat Kondor, at first as Oberleutnant zur See, then from 1933 on as Lieutenant (German: Kapitänleutnant).

From November 1941 to January 1944, he was head of Division III Radio Intelligence (SKL Chef MND III)) of the Departmental Group Chief of Naval Communication Services (German: Amtsgruppe Marinenachrichtendienst) within the Seekriegsleitung (SKL).