All four ships served with the main fleet in the interwar period, where they were primarily occupied with training exercises and fleet reviews. During the Spanish Civil War, "Gorizia" evacuated Italian nationals and "Pola" took part in non-intervention patrols. All four ships supported the Italian invasion of Albania in April 1939, shortly before the outbreak of World War II. After Italy joined the wider conflict in 1940, the four ships saw extensive action in the Mediterranean Sea against British forces. The ships took part in the battles of Calabria and Cape Matapan, and in the latter engagement, "Zara", "Pola", and "Fiume" were all sunk in a one-sided night action with three British battleships.