The Italian submarine Axum was an Adua-class submarine built in the 1930s, serving in the Regia Marina during World War II. She was named after an ancient city of Axum in Ethiopia.

The Adua-class submarines were essentially repeats of the preceding Perla class. They displaced 680 long tons (690 t) surfaced and 844 long tons (858 t) submerged. The submarines were 60.18 meters (197 ft 5 in) long, had a beam of 6.45 meters (21 ft 2 in) and a draft of 4.7 meters (15 ft 5 in).

For surface running, the boats were powered by two 600-brake-horsepower (447 kW) diesel engines, each driving one propeller shaft. When submerged, each propeller was driven by a 400-horsepower (298 kW) electric motor. They could reach 14 knots (26 km/h; 16 mph) on the surface and 7.5 knots (13.9 km/h; 8.6 mph) underwater. On the surface, the Adua class had a range of 3,180 nautical miles (5,890 km; 3,660 mi) at 10.5 knots (19.4 km/h; 12.1 mph), submerged, they had a range of 74 nmi (137 km; 85 mi) at 4 knots (7.4 km/h; 4.6 mph).

The boats were armed with six internal 53.3-centimeter (21.0 in) torpedo tubes, four in the bow and two in the stern. They were also armed with one 100-millimeter (4 in) deck gun for combat on the surface. The light anti-aircraft armament consisted of one or two pairs of 13.2 mm (0.52 in) machine guns.

Axum was built at the Cantieri Riuniti dell'Adriatico (CRDA) shipyard in Monfalcone, Italy. She was laid down on 8 February 1936 and launched on 27 September of the same year. The submarine was commissioned on 2 December 1936. On 20 March 1937 after a brief training, she was assigned to 23rd Submarine Squadron in Naples. Between 27 August and 5 September she performed a secret mission on behalf of the Spanish Nationalists in the Strait of Sicily but did not detect any targets.

Between 1937 and 1940 the submarine underwent intensive training out of her base in Naples. In 1940 Axum was assigned to 71st Squadron (VII Submarine Group) headquartered at Cagliari, but her operational base continued to be Naples. After Italy's entrance into World War II she was mainly operating in the western Mediterranean Sea.

In June 1940 she was deployed south of Sardinia. On 4–5 July Axum patrolled of the coast of northern Algeria. On 9–11 July the submarine relocated to patrol off the island of La Galite, then moved southwest of the island of Sant'Antioco. In the afternoon of 9 November Axum left Cagliari and was sent to patrol off La Galite along with four other submarines (including Alagi and Aradam) as a screen to the British Operation Coat. Later the same day, shortly after 19:00, she detected engine noises but the distance was far too great to attempt an attack. On 12 November 1940, she again detected weak noises through her hydrophones, but again the distant was far too great to attempt an attack. On 27 November, while patrolling south of Sardinia, at 21:35 three destroyers were sighted and Axum submerged to avoid detection.

In January 1941 she was deployed to the coast of Algeria and Tunisia. On 16 June, Axum, was sent to patrol between Ras Uleima, and Marsa Matruh to prevent coastal bombardments by British naval ships conducted in support British troops retreat. On 20 June, the submarine received orders to move closer to Benghazi. On 23 June, around 22:26 a ship was sighted heading west and Axum launched a torpedo, but it missed due to irregular running. Axum launched a second torpedo, but it also missed the ship, passing a few meters by the stern. The ship returned fire and the submarine was forced to dive and get through a brief but intense depth charge attack, without suffering any damage. From 19 to 28 July Axum patrolled off Tobruk and detected intense aerial and naval activity, but there were no attacks.