Which ocean current flows completely around Antarctica?

The ocean current that flows completely around Antarctica is the Antarctic Circumpolar Current.

Also called the West Wind Drift, it moves from west to east around the continent, circulating clockwise when viewed from the South Pole. It is able to form a continuous ring because no continent blocks the Southern Ocean at the latitudes where it flows.

The current links the Atlantic, Indian, and Pacific oceans and is widely regarded as the strongest current system in the global ocean. Estimates place its average transport at roughly 137 Sverdrups, with one Sverdrup equal to one million cubic metres of water per second.

The Antarctic Circumpolar Current also helps isolate Antarctica from warmer subtropical waters, supporting the continent's immense ice sheet. Its associated fronts and upwelling bring nutrients toward the surface, feeding ecosystems built around phytoplankton, krill, fish, seabirds, seals, and whales. It should not be confused with a western boundary current such as the Gulf Stream.