Following Italy's entry into the war in May 1915, Admiral Spaun would be among the most regularly used ships throughout the rest of the year against the Italians in the Adriatic. However, her mechanical problems prevented her from engaging in the same number of raids and sorties as the Novara-class cruisers. During this time, Admiral Spaun spent most of her time in service in the northern Adriatic, providing cover for Austro-Hungarian ships conducting mine-laying and mine-sweeping operations. Nevertheless, she did participate in some raids in the southern Adriatic in a secondary role. On the night of 28 December 1915, Helgoland and five destroyers participated in a raid on French and Italian ships. During this raid, Helgoland rammed and sank the French submarine between Brindisi and the Albanian port of Durazzo, before attacking shipping in Durazzo the following morning. After sinking several ships in the port, two of the Austro-Hungarian destroyers accompanying Helgoland struck mines and one sank. In response to these setbacks, Novara, Admiral Spaun, and the were mobilised to support Helgoland and the Austro-Hungarian destroyers. Helgoland was unscathed in the operation and managed to evade the Allied pursuit when darkness fell, rendezvousing with the reinforcements sent out to escort her back to Cattaro. Admiral Spaun saw much less action throughout 1916 as mechanical issues remained a problem. Instead, she remained on duty in more secondary roles and underwent a refit to strengthen her anti-aircraft and torpedo weaponry. Despite these setbacks, throughout most of the war Admiral Spaun and the Novara-class ships served as the "real capital ships of the Adriatic", as many of the larger ships of the Austro-Hungarian Navy—such as the Tegetthoff-class battleships—remained at port in Pola between May 1915 and June 1918.
