"Roma" was commissioned into the "Regia Marina" on 14 June 1942, but a severe fuel shortage in Italy at that time prevented her from being deployed; instead, along with her sister ships and , she was used to bolster the anti-aircraft defenses of various Italian cities. In this role, she was severely damaged twice in June 1943, from bomber raids on La Spezia. After repairs in Genoa through all of July and part of August, "Roma" was deployed as the flagship of Admiral Carlo Bergamini in a large battle group that eventually comprised the three "Littorio"s, eight cruisers and eight destroyers. The battle group was scheduled to attack the Allied ships approaching Salerno to invade Italy (Operation "Avalanche") on 9 September 1943, but the news of the 8 September 1943 armistice with the Allies led to the operation being cancelled. The Italian fleet was instead ordered to sail to La Maddalena (Sardinia) and subsequently to Malta to surrender to the Allies.