In principle, all residents of Japan between the ages of 20 to 59 must enroll in the National Pension System, regardless of nationality.
The enrollment procedure is handled by the ward office of the ward where your address is registered.
＊However, foreigners will no longer be able to join the National Pension System once they lose their address from Japan. In addition, the period of residence abroad is not counted toward the old-age basic pension.
＜Lump-Sum Withdrawal Payments for Foreigners＞
A Lump-Sum Withdrawal Payment is available for foreigners who have paid insurance premiums but have returned to their home country without being eligible to receive benefits. Foreigners who have paid National Pension System contributions or have been enrolled in the Employees’ Pension System for six months or more and are ineligible for pension benefits can receive a Lump-sum Withdrawal Payment if they file a claim within two years after leaving Japan. The process can be initiated by submitting a claim to the Japan Pension Service through mail.
For more information on the National Pension System, please see the following URL.