She served as a seaplane base in Valona during World War I and supported the Allied response during the Battle of the Strait of Otranto in 1917.

[3][5] The Italian Regia Marina had previously experimented with seaplane carriers with the conversion of the protected cruiser Elba in 1914.

Accordingly, the navy requested funding to purchase a merchant ship and convert it into a seaplane carrier, which was approved in the year's naval budget.

The Naval Staff concurred and purchased it, and in addition to a seaplane carrier, the ship would also be used as a submarine tender.

The short forecastle and quarterdeck were extended to make the ship flush-decked, though the sides remained open to provide ventilation and light to what had been the upper deck.

Forward visibility was poor, so lookouts had to be stationed in the crow's nest or on the searchlight platform in front of the hangar.

The hangars had completely opened sides that could be sealed with waterproof tarps Cranes were fitted to lower and raise the aircraft into the water, where they would take off or land.

Fuel storage amounted to 770 cubic meters (27,000 cu ft), which was divided between thirty-two separate tanks.

The extensive subdivision of the tanks improved stability by dispersing the weight of fuel and minimized the effect of moving liquid in the hull.

[12] Europa originally carried a complement of Macchi L.1 seaplanes and Curtiss Model H flying boats.

The L.1 was used as a fighter and a bomber, while the Model H was used for training and limited bombing operations, as it was an older design that had been superseded by more modern aircraft.

From June to November 1918, Europa operated a few Ansaldo SVAI seaplane fighters, though these proved to be unreliable and not particularly maneuverable.

[13] After completing the conversion in May 1915, the ship spent much of the rest of the year assembling and training the crew and conduct sea trials.

[3][14] Valona lacked any harbor facilities beyond the outer moles, and so the ability to operate aircraft under such conditions proved to be invaluable.

She had three aircraft ready the morning of the battle on 15 May,[16] and after reports of the Austro-Hungarian attack reached the Italian command, her aircraft—FBA flying boats—sortied to search for the hostile vessels at 05:00, once there was enough light to see.

The aircraft scored thirty-three hits on the Austro-Hungarian naval air station in the harbor and significantly degraded its ability to conduct operations for several months.

Over the course of the war, the ship's aircrews flew a total of 1,884 missions, of which 1,500 were reconnaissance flights and more than 200 were combat sorties, during which they dropped some 2,000 bombs.

[19] In the postwar period, naval aviation fell out of favor, particularly as a result of Giulio Douhet's views on air power, namely his preference for strategic bombing over other types of tactical and operational doctrines.