Any of several ocean currents driven by the southeast trade winds flowing over the tropical oceans of the Southern Hemisphere.

In the Atlantic Ocean it flows westward between the equator and 20 degrees. Part crosses the equator and flows northwest along the coast of South America as the Guiana current . The rest turns to the left and flows south along the coast of Brazil as the Brazil current.

In the Pacific Ocean, the south equatorial current crosses the ocean from east to west between the latitudes of approximately 3 degrees and 10 degrees. Much of it turns south in mid-ocean forming a large anticyclonic whirl. The portion that continues across the ocean divides as it approaches Australia, part moving north toward New Guinea and part turning south along the east coast of Australia as the east Australia current .

In the Indian Ocean, the south equatorial current is displaced rather far to the south, and as it approaches the east coast of Africa it turns south, joining the Agulhas current .