Assigned to the Pacific Station during 1914–15, "Encounter" was part of the force which occupied German New Guinea. In the course of that operation, she captured the steamer "Zambezi" on 12 August and, on 14 September, bombarded Toma Ridge to support the Australian Military and Naval Expeditionary Force which was besieging the town. That action made her the first RAN ship to . She covered the landing at Madang on 24 September. In October, she was sent to the Fiji-Samoa area. During a patrol of the region on 25 April 1915, "Encounter" captured the German sailing vessel "Elfriede".