Napoli saw action in the Italo-Turkish War in 1911 and 1912; she took part in the attack on Derna, Libya, and the amphibious assaults on the islands of Rhodes and the Dodecanese in the Aegean Sea.

Napoli remained in service during World War I in 1915–1918, but saw no action as a result of the cautious policies of both the Italian and Austro-Hungarian navies.

The Navy specified a vessel that would be more powerful than contemporary armored cruisers and faster than foreign pre-dreadnought battleships on a displacement of no more than 13,000 long tons (13,210 t).

For the duration of the conflict, Napoli served in the 1st Division of the 1st Squadron with her three sister ships, under the command of Vice Admiral Augusto Aubry.

After the outbreak of war, Napoli, her sister Roma, and the armored cruisers Pisa and Amalfi, were sent to blockade Tripoli in North Africa.

On 2 October, the battleship Benedetto Brin and the training squadron arrived to relieve Napoli and the other ships, which thereafter left to rejoin the flagship, Vittorio Emanuele.

[7] On 15 October, Napoli, which had been detached to reinforce the armored cruisers in the 2nd Division, 1st Squadron, arrived in Derna, Libya in company with several troopships.

In early 1912, most of the fleet, including Napoli, withdrew to Italy for repairs and refit, leaving only a small force of cruisers and light craft to patrol the North African coast.

Over the next two months, the ships cruised in the Aegean to prevent the Turks from attempting to launch their own amphibious operations to retake the islands Italy had seized in May.

The 1st Division left port on 14 October, but was recalled later that day, when the Ottomans had agreed to sign a peace treaty to end the war.

Italy's traditional naval rival, the Austro-Hungarian Navy, was the primary opponent in the conflict, and lay directly across the narrow Adriatic Sea.

Admiral Paolo Thaon di Revel, the Italian Naval Chief of Staff, understood that Austro-Hungarian submarines presented too serious a threat to his capital ships for him to mount an active fleet policy.

Instead, Revel decided to implement blockade at the relatively safer southern end of the Adriatic with the battle fleet, while smaller vessels, such as the MAS boats conducted raids on Austro-Hungarian ships and installations.

[12] On 14–15 May 1917, three light cruisers of the Austro-Hungarian Navy raided the Otranto Barrage; in the ensuring Battle of the Strait of Otranto, Napoli and her sisters raised steam to assist the Allied warships, but the Italian commander refused to permit them to join the battle for fear of risking their loss in the submarine-infested Adriatic.