The Glauco class was a pair of submarines ordered by the Portuguese government, but were taken over and completed for the Regia Marina (Royal Italian Navy) during the 1930s.

[1] For surface running, the boats were powered by two 1,500-brake-horsepower (1,119 kW) diesel engines, each driving one propeller shaft.

[2] The boats were armed with eight internal 53.3 cm (21 in) torpedo tubes, four each in the bow and stern.

They were also armed with two 100 mm (3.9 in) deck guns, one each fore and aft of the conning tower, for combat on the surface.

[2] Glauco was badly damaged by the British destroyer HMS Wishart and scuttled by her own crew on 27 June 1941, west of Gibraltar; Otaria was surrendered to the Allies in 1943 and used for training until it was sent to the junkyard in 1948.