Among them were enlargement of the false tower at the top, more modern engines, installation of a radiogoniometer that could be controlled from inside the ship.

[1] Corallo was built by CRDA at their shipyard in Monfalcone, laid on 1 October 1935, launched on 2 August 1936 and completed on 26 September 1936.

In 1939 Corallo returned to active duty, and was assigned to the 72nd Squadron (VII Submarine Group) based at Cagliari where she remained until the end of her career.

[2] Italy's entry into World War II found Corallo at Monfalcone undergoing repairs and maintenance which were finished in late August 1940.

On September 3, 1940, Corallo, under command of captain Loris Albanese, was sent to patrol an area 60 miles south of Crete, between Gaudo and Alexandria.

Since the damage to submarine could not be repaired by means available at sea, Corallo was forced to interrupt her mission and headed to Tobruk which she reached on September 18, 1940.

[6] On November 5, 1940, Corallo and four other submarines (Topazio, Fratelli Bandiera, Pier Capponi and Goffredo Mameli) were deployed about 90 miles south-east of Malta with the task of intercepting a British convoy, part of Operation "Coat".

[10] In February 1941 she was on patrol north of Cape Bougaroun, but engine problems forced the submarine to return to the base.

In April 1941 she patrolled south of Sardinia, but her mission was cut short again, this time because of the adverse weather conditions.

[10] On November 3, 1941, Corallo under command of captain Andreani was deployed west of Malta as a protective screen for a large Italian "Beta" convoy travelling to Libya.

Force K managed to leave Malta without Corallo being able to detect it since it did not pass through her area of operation, but rather through the one controlled by Luigi Settembrini.

[10] In early December she was deployed together with Alagi, Argento, Bronzo, Galatea, Porfido, Volframio, Mocenigo, Diaspro and Malachite in the western Mediterranean, as a defensive screen protecting Axis convoys to Tunis.

At this point, according to some sources, Corallo tried to engage HMS Enchantress with her deck gun, but the British sloop accelerated and rammed the submarine.

While HMS Enchantress suffered serious collision damage even to her inner structures, Corallo had the worst of it, and sunk with all hands (commander Guidi, 5 officers, and 43 other crew members) in the position 36°58′N 05°07′E / 36.967°N 5.117°E / 36.967; 5.117.