'Crozier III' was a British naval undertaking by a motor gun boat to land men and supplies of the Special Operations Executive on Bonaparte beach near Plouha in the St Brieuc Bay area of German-occupied north-western France (9/10 August 1944).

The boat in question was Lieutenant R. F. Seddon’s MGB-718 of the 15^th Motor Gun Boat Flotilla, and this departed Dartmouth for the operation.