HMAS ENCOUNTER, (cruiser), shelled German positions at Toma, New Britain. This was the first occasion a ship of the RAN had fired on an enemy.
HMA Submarine AE1, (LCDR T. F. Besant, RN), was lost with 2 officers and 32 ratings, while patrolling off the Duke of York Island. The wreck of the submarine was found in December 2017.
HMAS WARREGO, (torpedo boat destroyer), captured the German steamer NUSA at Kavieng.