About This Unit
When war with Germany was declared on 4 August 1914, Pioneer was at Port Phillip Bay, Melbourne. The following day she sailed for Fremantle to operate on patrol on the Western Australian coast. Operations began on 16 August, and on that day, some eight miles west of Rottnest Island, Pioneer captured the German steamer Neumunster (4424 tons) and took her into Fremantle. On 26 August she captured a second ship, the 4994 ton Norddeutcher-Lloyd vessel Thuringen, also off Rottnest Island. Neumunster was taken over by the Commonwealth Government as a prize of war and renamed Cooee. Thuringen was renamed Moora and handed over to the Indian Government for service as a troopship.
On 4 September Pioneer proceeded from Fremantle on patrol to Darwin, calling at Port Hedland and Broome enroute.
On 1 November 1914 Pioneer sailed as part of the escort to the First Australian Convoy comprising 38 transports but, just as she was taking up position between the Australian and New Zealand divisions, her engines broke down and the Flagship, HMS Minotaur, ordered her to return to Fremantle. Thus she probably missed encountering the German cruiser Emden instead of HMAS Sydney (I) as she was under orders to diverge from the convoy route to inspect the Cocos Islands.
On 24 December 1914 the Admiralty requested the aid of Pioneer as a blockading ship on the German East African coast, where the German cruiser Konigsberg had taken shelter up one of the mouths of the Rufigi River a few miles south of Zanzibar.
Sailing from Fremantle on 9 January 1915, Pioneer proceeded to the Cocos Islands, where as she coaled from her attendant collier her crew inspected the wreck of the Emden, destroyed by Sydney on 9 November 1914. After leaving the Cocos Islands, she proceeded to Diego Garcia in the Chagos Archipelago and then to Zanzibar which was reached on 6 February 1915.