Moso bamboo (Phyllostachys pubescens) forests are now expanding in Asian countries such as Taiwan and Japan. It is possible that the bamboo expansion could change local water cycling there. Transpiration is one of important water cycling components. While, there have been a few studies examining transpiration in bamboo forests. Using sap-flux methods, we clarified larger stand transpiration in a Moso bamboo forest than surrounding coniferous forests in Kyushu, Japan. On the other hand, the generality of the results was still unknown, as the conditions of Moso bamboo forests such as stand density and climate conditions are different between places. To develop a general model for assessing potential impacts of bamboo expansion on water cycling, this study conducted the year-round stand transpiration estimates based on sap flux measurements in four Moso bamboo forests, covering different stem density and climate conditions, in Kyoto, Fukuoka, and Taiwan. Using the data set, this study revealed that stand transpiration for the four bamboo forests was successfully reproduced using a canopy conductance model with a parameter set. This suggests that the spatial variations in stand transpiration were primarily caused by meteorological conditions and the culm age distribution in each stand.