The Bremer Commonwealth Marine Reserve is a 4472 km2 marine reserve, with a depth range of about 15–5000 m, lying in the Southern Ocean off the southern coast of Western Australia about 50 km south-east of the town of Bremer Bay. An area of 284 km2, comprising the northernmost section adjoining Western Australia’s coastal waters, has been zoned as a marine national park (IUCN Category II), with the remainder as multiple use or special purpose zones (IUCN Category VI).