Re Umberto ("King Humbert") was a Re Umberto-class ironclad battleship built for the Italian Regia Marina (Royal Navy) in the 1880s, the lead ship of her class.

Re Umberto carried out various duties during her service career, including large-scale fleet maneuvers and diplomatic missions in Europe.

In 1918 her armament was exchanged for a number of 3-inch (76 mm) guns and trench mortars as part of her role as the lead ship in the planned Italian assault on the main Austro-Hungarian naval base at Pola.

Specific figures for her cruising radius have not survived, but the ships of her class could steam for 4,000 to 6,000 nautical miles (7,400 to 11,100 km; 4,600 to 6,900 mi) at a speed of 10 knots (19 km/h; 12 mph).

[1] Re Umberto was armed with a main battery of four 343 mm (13.5 in) 30-caliber guns, mounted in two twin-gun turrets, one on either end of the ship.

Close-range defense against torpedo boats was provided by a battery of sixteen 120 mm (4.7 in) guns in casemates in the upper deck, eight on each broadside.

The ships alternated between the two in February of each year; in 1895, Re Umberto was assigned to the Reserve Squadron, along with the older battleships Ruggiero di Lauria, Italia, and Lepanto.

On July 20 a hundred Italian officers with the Duke of Genoa and Admirals Accini and Grandville inspected the dockyard.

[9] The following year, the ships were transferred to the Reserve Squadron, along with the three Ruggiero di Laurias and the ironclad Enrico Dandolo, three cruisers, and sixteen torpedo boats.

[12] At the time, Re Umberto and her two sisters were assigned to the Training Division, along with the old armored cruiser Carlo Alberto, under the command of Rear Admiral Raffaele Borea Ricci D'Olmo.

By the morning of the 4th, the ships' gunfire had silenced the guns in the fort, allowing landing forces to go ashore and capture the city.

[18] The following month, Re Umberto and her sisters, along with six torpedo boats, escorted a convoy carrying an infantry brigade to Buscheifa, one of the last ports in Libya still under Ottoman control.

[19] The Training Division then returned to Italy, where they joined the escort for another convoy on 3 August, this time to Zuara, the last port in Ottoman hands.

The ships covered the landing two miles east of Zuara two days later, which was joined by supporting attacks from the west and south.

Towed to La Spezia in June 1915, after having been stricken from the Navy List on 10 May 1914, she became a depot ship for the dreadnought Andrea Doria.