 During World War I, "Pisa"s 76 and 47 mm guns were replaced by twenty 76/40 guns; six of these were anti-aircraft (AA) guns while "Georgios Averof" received one additional 76 mm AA gun.During her 1925 refit, the latter ship had her light armament changed to four 76 mm low-angle guns, two 76 mm AA guns, four 47 mm low-angle guns and five 40 mm AA guns.All three ships were protected by an armored belt that was thick amidships and reduced to at the bow and stern.