Early in World War I, "Árpád" was transferred to the Austro-Hungarian Navy's IV Division after the first new s came into service. At around the same time, "Árpád", her sister ships and and the remainder of the Austro-Hungarian Navy were mobilized to support the flight of and from 28 July to 10 August 1914. The two German ships were stationed in the Mediterranean and were attempting to break out of the strait of Messina, which was surrounded by British vessels. After breaking out, the German ships planned to steam to Turkey. After the Germans successfully broke out of Messina, the Austro-Hungarian Navy was recalled. The fleet had by that time advanced as far south as Brindisi in southeastern coast of Italy. After Italy entered the war on the side of France and Great Britain, the Austro-Hungarian Navy bombarded several Italian port cities along the Adriatic coast. "Árpád" took part in the Bombardment of Ancona on 23 May 1915.