Abstract Sea surface temperature (SST) in the Indonesian Seas drives atmospheric deep convection, influencing regional and global climate. Yet, the processes controlling SST in this region remain poorly understood. Using a high‐resolution regional model that explicitly resolves internal tides, we show that tidal displacements lift cold thermocline water into the surface ocean, exposing it to vigorous surface mixing and thus enhancing the surface‐interior heat exchange. The heat exchange facilitated by tides shows strong seasonality, intensifying during monsoons in areas where the mixed layer is deep and the thermocline is shallow. This tidal exposure mechanism augments, with comparable impact, the mixing driven by internal tide breaking in the interior. However, it dominates the tidal impacts for the vertical heat exchange in the upper ocean. This novel pathway for vertical heat exchange must be represented in coarse‐resolution climate models to improve simulations of SST and air–sea interactions in the region.