Commissioned into service in the Italian Regia Marina (Royal Navy) in 1913, she served in World War I, playing an active role in the Adriatic campaign.

The squadron, under the command of Capitano de fregata (Frigate Captain) P. Orsini, was based at Taranto, although although either Impetuoso or Indomito or both were visiting La Spezia that day.

[3] In the early hours of 17 July 1915 Intrepido, Animoso, Irrequieto, and Quarto bombarded the radiotelegraph station and other Austro-Hungarian military installations on Šipan (known to the Italians as Giuppana), an island off the coast of Dalmatia.

[4] On 9 July 1916 Irrequieto (now under the command of an officer named Ponza di San Martino) and Impetuoso set out in pursuit of the Austro-Hungarian scout cruiser Novara, which had attacked the Otranto Barrage in the Strait of Otranto and sunk the naval drifters — armed fishing boats that patrolled anti-submarine barriers — Astrum, Claivis, and Spei, but Novara reached the Austro-Hungarian naval base at Cattaro before they could intercept her.

[4] On 11 June 1917 Irrequieto, Insidioso, and the torpedo boats Airone and Ardea provided distant support to 10 Italian seaplanes sent to bomb Durrës.