Eradication programs are being implemented for 2 sweetpotato weevil pests, Cylas formicarius and Euscepes postfasciatus, in the Ryukyu Islands located in the southernmost part of Japan by the application of the sterile insect technique (SIT). As it is essential for the implementation of the programs to assess the dispersal ability of the weevils, recent studies were reviewed. Both the flight and walking ability of C. formicarius was much higher in males than in females when determined in the laboratory. Synthesized sex pheromone of C. formicarius has been used as a strong lure to capture the males in the field. Results of the mark-recapture experiments suggest that a distance of at least 2 km is needed for the range of the buffer zone to separate the SIT target area from others. Since E. postfasciatus is unable to fly, only the walking ability was evaluated in the laboratory, indicating that the females exhibited a fairly higher locomotion activity compared with the males. Since no effective attractant for E. postfasciatus has been identified yet, information on the dispersal activity in the field is limited. Fundamental studies should be conducted to determine the dispersal ability of both weevil pests to implement successfully the eradication programs.