Delfino was designed by marine engineer Giacinto Pullino at the La Spezia Navy Yard.

Accounts vary as to the date of her construction; it seems that she was built as an experimental craft and was under trials for several years before being accepted by the Italian Navy.

Delfino was modernized between 1902 and 1904; she was equipped with a 130 hp FIAT petrol engine which increased her surface speed to 10 knots (19 km/h; 12 mph), and her surface range to 165 nautical miles (306 km; 190 mi) cruising at 6 knots (11 km/h; 6.9 mph).

The torpedo tube was changed to 450 mm (18 in) and her conning tower was enlarged for surface navigation.

[1] Delfino was commissioned on 1 April 1895 (official records say 1896) and she served with the Regia Marina into the 20th century.