The wind driven circulation is mainly horizontal, and occurs in the upper few hundreds of meters of the ocean. Broadly speaking the surface currents form five great anticyclonic gyres, north and south of the Equator in the Pacific and Atlantic and south of the Equator in the Indian Ocean. Fast-flowing warm western boundary currents such as the Gulf Stream transport heat from the tropics to mid-latitudes on the western side of each ocean. On the eastern side, cold water flows back towards the equator as broad, slow 'eastern boundary currents' such as the Canary Current and the Benguela. The Northern Indian circulation is driven by the monsoon in summer, but weakens and reverses direction in winter.

In the Southern Hemisphere the westerlies drive the Antarctic Circumpolar Current, which circles the Antarctic continent from west to east. In the Northern Hemisphere the presence of land leads to a more complicated current system at high latitudes.