Source waters of the Indo-Pacific equatorial thermocline are studied with a high-resolution ocean model. In the annual mean fields, tropical and subtropical overturn-ing cells are found that upwell at the equator and downwell at 5 degrees and 20 degrees poleward of the equator re-spectively. Tropical cells are common in ocean models, but their role in ventilating the equatorial thermocline is ob-scure because the downwelled water is too warm to match the subsurface equatorial waters. The tropical cells are much weaker when the overturning is considered in density coordi-nates. When high-frequency mass fluxes are included trop-ical cells are compensated by an eddy-induced overturning. Seasonal variations and tropical instability waves are respon-sible for the compensation. It follows that only subtropical cells transfer surface water to the equatorial thermocline. Strong tropical cells are shown to be an artefact.