This is a list of the Roman and Eastern Catholic dioceses in Oceania.
Because Oceania is one of the more sparsely populated areas of the world, the majority of its dioceses are located in Australia and New Zealand, although they range as far as the Midway Atoll in the Pacific Ocean to Tasmania.
Exempt archdioceses are immediately subject to the Holy See: The ecclesiastical Province of Adelaide covers the whole of the state of South Australia, and the territory of the Northern Territory The ecclesiastical Province of Brisbane covers the whole of the state of Queensland The province covers the whole of the state of Victoria The ecclesiastical Province of Perth covers all of Western Australia The province covers most of the state of New South Wales