Designed in parallel with the Mameli-class submarines, the Pisani class was larger to accommodate more fuel and give them more range.
They displaced 880 metric tons (866 long tons) surfaced and 1,057 metric tons (1,040 long tons) submerged.
The submarines were 68.2 meters (223 ft 9 in) long, had a beam of 6.09 meters (20 ft) and a draft of 4.93 meters (16 ft 2 in).
They had an operational diving depth of 90 meters (300 ft).
Their crew numbered 48 officers and enlisted men.

For surface running, the boats were powered by two 1,500-brake-horsepower (1,119 kW) diesel engines, each driving one propeller shaft.
When submerged each propeller was driven by a 550-horsepower (410 kW) electric motor.
Like the Mamelis, their stability was poor and they had to be modified with bulges after completion.
This reduced their speeds from  17.25 knots (31.95 km/h; 19.85 mph) on the surface and 8.75 knots (16.21 km/h; 10.07 mph) underwater to 15 knots (28 km/h; 17 mph) and 8.2 knots (15.2 km/h; 9.4 mph) respectively.
On the surface, the Pisani class had a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 8 knots (15 km/h; 9.2 mph); submerged, they had a range of 70 nmi (130 km; 81 mi) at 4 knots (7.4 km/h; 4.6 mph).

The boats were armed with six 53.3-centimeter (21 in) torpedo tubes, four in the bow and two in the stern for which they carried a total of nine torpedoes.
They were also armed with a single 102-millimeter (4 in) deck gun forward of the conning tower for combat on the surface.
Their anti-aircraft armament consisted of two 13.2-millimeter (0.52 in) machine guns.
Designed in parallel with the Mameli-class submarines, the Pisani class was larger to accommodate more fuel and give them more range. They displaced 880 metric tons (866 long tons) surfaced and 1,057 metric tons (1,040 long tons) submerged. The submarines were 68.2 meters (223 ft 9 in) long, had a beam of 6.09 meters (20 ft) and a draft of 4.93 meters (16 ft 2 in). They had an operational diving depth of 90 meters (300 ft). Their crew numbered 48 officers and enlisted men.
For surface running, the boats were powered by two 1,500-brake-horsepower (1,119 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 550-horsepower (410 kW) electric motor. Like the Mamelis, their stability was poor and they had to be modified with bulges after completion. This reduced their speeds from  17.25 knots (31.95 km/h; 19.85 mph) on the surface and 8.75 knots (16.21 km/h; 10.07 mph) underwater to 15 knots (28 km/h; 17 mph) and 8.2 knots (15.2 km/h; 9.4 mph) respectively. On the surface, the Pisani class had a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 8 knots (15 km/h; 9.2 mph); submerged, they had a range of 70 nmi (130 km; 81 mi) at 4 knots (7.4 km/h; 4.6 mph).
The boats were armed with six 53.3-centimeter (21 in) torpedo tubes, four in the bow and two in the stern for which they carried a total of nine torpedoes. They were also armed with a single 102-millimeter (4 in) deck gun forward of the conning tower for combat on the surface. Their anti-aircraft armament consisted of two 13.2-millimeter (0.52 in) machine guns.
Pisani-class submarine