During the early stages of World War I, "Parramatta" operated with the Australian fleet in the search for the German East Asia Squadron, then was involved in the capture of German colonies in the South Pacific region, including German New Guinea, and the consolidation of Allied occupation in these regions. On 5 February 1915, "Yarra", "Parramatta", and sailed for Australia, where they were used for convoy escort duties along the continent's eastern coast until August. The ships were refitted at Sydney, then sent to patrol the Far East. "Yarra" returned to Australia on 8 May 1916, and patrolled home waters until May 1917, when she and her sister ships were ordered to Malta.