ABSTRACT The recruitment strategy of swimming crabs, Portunus trituberculatus , was investigated by field observations and numerical experiments in Hiuchi‐Nada, Japan. Calculated dispersal patterns of zoeal and megalopal stages in a three‐dimensional numerical model reproduce observed patterns accurately. The temporal change of vertical migration patterns between the 1st and 2nd zoeas and the 3rd and 4th zoeas plays an important role in the process of recruitment of P. trituberculatus from spawning ground to nursery ground.