Analysis of surface flux data suggests that the South China Sea throughflow is a conveyor belt transferring up to 0.2 PW (1 PW = 1 ¿ 1015W) of heat and 0.1 Sv (1 Sv = 1 ¿ 106 m3 s-1) of freshwater from the South China Sea into the Indonesian maritime continent. As surface heat and freshwater fluxes display substantially different temporal variations with the South China Sea throughflow, we hypothesize that the South China Sea acts as a heat capacitor, storing heat in certain years and releasing it in others. Results from a high-resolution general circulation model confirm this hypothesis, implying that the South China Sea is likely to play a more active role than previously thought in regulating the sea surface temperature pattern in the Indonesian maritime continent and its adjoining western Pacific and eastern Indian Oceans.