The Southern Ocean (SO) realm is the vast, cold marine region surrounding the continent of Antarctica. It is defined by the Antarctic Circumpolar Current, the world's strongest ocean current, which effectively isolates its waters from warmer northern oceans.

The Temperate Australasia (TU) marine realm encompasses the temperate waters surrounding the southern half of Australia and all of New Zealand. This region is characterized by high levels of marine endemism, particularly among its seaweeds, fish, and invertebrates.

The Temperate Southern Africa (TF) realm covers the temperate waters where the Atlantic and Indian Oceans meet. It includes the coastal and shelf waters of South Africa and Namibia, as well as remote islands like Amsterdam and Saint-Paul.