The height where cumulus convection over tropical oceans directly transports air from the boundary layer is statistically investigated, making use of the NASA Pacific Exploratory Mission-Tropics B (PEM-Tropics B) observed data. The cumulus convection detrainment levels are inferred by high CH3I concentrations and relative humidity. The relationship between the injection height and stability is also discussed. Tropical cumulus convection directly transported boundary layer air to the 350--600 hPa and 750--800 hPa levels. These pressure levels coincided with the heights where stable layers were frequently observed. On the other hand, the cumulus convection infrequently transported boundary layer air directly to the 600--750 hPa levels, being consistent with the fact that stability around these levels was weak.