The San Giorgio class consisted of two armored cruisers built for the Royal Italian Navy (Regia Marina) in the first decade of the 20th century.

The ship's anti-aircraft armament was augmented when she was deployed to Tobruk, Libya to reinforce the port's defenses after Italy declared war on Britain in May 1940.

San Giorgio's two shafts, pair of 19,500-indicated-horsepower (14,500 kW) VTE steam engines and Blechynden boilers differed only slightly from those used by the Pisas.

The turbines used steam provided by Babcock & Wilcox boilers at a working pressure of 210 psi (1,448 kPa; 15 kgf/cm2)[4] to reach their designed output of 23,000 shp (17,000 kW).

[5] The main armament of the San Giorgio-class ships consisted of four Cannone da 254/45 A Modello 1907[Note 1] guns in electrically powered, twin-gun turrets fore and aft of the superstructure.

[6] The ships mounted eight Cannone da 190/45 A Modello 1908 in four electrically powered twin-gun turrets, two in each side amidships, as their secondary armament.

[5] San Giorgio ran aground in August 1911 off Naples-Posillipo;[10] heavily damaged, she was under repair until June 1912, missing most of the Italo-Turkish War.

San Marco supported the occupations of Benghazi and Derna, Libya during the war and bombarded the fortifications defending the entrance to the Dardanelles.

She was captured by the Germans when they occupied La Spezia on 9 September 1943; San Marcos was found at the end of the war half-sunk in the harbor there and was broken up in 1949.

[9] From 1930 to 1935, San Giorgio was based in Pola as a training ship, and was sent to Spain after the Spanish Civil War began in 1936 to protect Italian interests.

[14] In 1937–1938 she was reconstructed to serve as a dedicated training ship for naval cadets at the Arsenale di La Spezia: six boilers were removed and the remaining eight were converted to burn fuel oil which reduced her speed to 16–17 knots (30–31 km/h; 18–20 mph).

[19] Two days after Italy declared war on Britain on 10 June, the British light cruisers Gloucester and Southampton bombarded Tobruk and attacked San Giorgio, which was not hit during the engagement.

[19] San Giorgio was awarded the Gold Medal of Military Valour (Medaglia d'Oro al Valore Militare) for her performance at Tobruk.