 "U-566" had a displacement of when at the surface and while submerged.She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of .The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two Brown, Boveri & Cie GG UB 720/8 double-acting electric motors producing a total of for use while submerged.