The eastward flow of the equatorial counter-current is explained by the convergence of the two equatorial currents:

• The North Equatorial Current flows westward north of the equator.
• The South Equatorial Current flows westward south of the equator.

The convergence of these two westward-flowing currents in the equatorial region causes an upwelling of the subsurface water, resulting in the formation of the eastward-flowing equatorial counter-current.