Oceania is dominated by the Australian/New Zealand Type I plug at 230–240 V, 50 Hz — Australia, New Zealand, Fiji, Papua New Guinea, the Solomons, Samoa, Vanuatu and Tonga all use it. The Pacific island states under US influence (Marshall Islands, Micronesia, Palau) instead use Type A and B at 120 V, 60 Hz. There's no in-between: pick your adapter once you know which side of the Pacific your destination falls on.

14 countries in Oceania

Country	Plug types	Voltage	Hz
Australia	I	230 V	50
Fiji	I	240 V	50
Kiribati	I	240 V	50
Marshall Islands	A B	120 V	60
Micronesia	A B	120 V	60
Nauru	I	240 V	50
New Zealand	I	230 V	50
Palau	A B	120 V	60
Papua New Guinea	I	240 V	50
Samoa	I	230 V	50
Solomon Islands	I	230 V	50
Tonga	I	240 V	50
Tuvalu	I	230 V	50
Vanuatu	I	230 V	50