 After early peacetime training activity, and two fruitless missions in the Mediterranean Sea, the "Barbarigo" was assigned to the Atlantic theater, reaching its base in Bordeaux on 8 September 1940, after an unsuccessful patrol.From October 1940 to May 1941, she went on three missions around Irish waters, which obtained only the damaging of a merchantman.In July, she sailed to the west of the Strait of Gibraltar and obtained its first successes, sinking the British ship "Macon" (5135 tls) on 25 July, and then the oiler "Horn Shell" (8272 tls), before turning for port.