Kammala jumla mai zuwa: A daren 11 ga Nuwamba, 1940, "Giulio Cesare" da sauran jiragen ruwa na Italiya sun kasance a cikin tashar jiragen ruwa na Taranto lokacin da 21 Fairey Swordfish torpedo bombers suka kai musu hari daga jirgin sama na Birtaniya, tare da wasu jiragen ruwa da dama. Wani torpedo ya nutsar da "Conte di Cavour" a cikin ruwa mai zurfi, amma "Giulio Cesare" ba a buga shi ba a lokacin harin. Ta shiga cikin yakin Cape Spartivento a ranar 27 ga Nuwamba, 1940, amma ba ta kusa kusa da kowane jirgi na Birtaniya don harba su ba. Jirgin ya lalace a watan Janairun 1941 ta hanyar raguwa daga kusan kuskuren yayin wani harin iska a kan Naples ta hanyar Vickers Wellington bombers na Royal Air Force; an kammala gyare-gyare a Genoa a farkon Fabrairu. A ranar 8 ga Fabrairu, ta tashi daga Strait of Bonifacio don tsayar da abin da Italiyanci suka yi tsammani jirgin Malta ne, amma a zahiri ya kai hari kan Genoa. Ta kasa yin hulɗa da kowane dakarun Birtaniya. Ta shiga cikin
Yaƙin Sirte na farko a ranar 17 ga Disamba, 1941, yana ba da kariya mai nisa ga wani jirgi mai zuwa Libya, kuma ya ɗan ɗanɗana rundunar da ke rakiyar wani jirgi na Burtaniya. Har ila yau, ta ba da kariya mai nisa ga wani jirgin ruwa zuwa Arewacin Afirka a farkon Janairu 1942. "Giulio Cesare" an rage shi zuwa jirgin horo bayan haka a Taranto kuma daga baya Pola. Bayan Italiyanci ya mika wuya a ranar 9 ga Satumba, 1943, ya tashi zuwa Taranto, ya sa wani tawaye kuma ya jimre da hare-haren da ba shi da tasiri daga jiragen sama biyar na Jamus a hanya. Daga nan sai ta tashi zuwa Malta inda ta isa ranar 12 ga Satumba don a tsare ta. Jirgin ya kasance a can har zuwa 17 ga Yuni 1944 lokacin da ta koma Taranto inda ta kasance har tsawon shekaru hudu masu zuwa.