Those Who Have or Will Acquire Foreign Citizenship

When living abroad, you may find it convenient to acquire the citizenship of that country.
 
However, if a person with Japanese nationality wishes to acquire foreign citizenship and naturalizes, applies/notifies to acquire citizenship, or restores the lost foreign citizenship at his/her own will, you will lose your Japanese nationality (Nationality Law Article 11).
 
In addition, if a parent or legal guardian takes measures to acquire foreign citizenship on behalf of a minor, it will be considered that the acquisition was made at their own will.
 
Once you acquire foreign citizenship at will and lose your Japanese nationality, you can only reacquire Japanese nationality by residing in Japan and applying for naturalization.
 
Furthermore, once you have lost Japanese nationality, you, your spouse or a relative within fourth degree of kinship MUST submit the Denaturalization Registration to the municipal office of your registered domicile within 1 month of learning the loss of nationality (if the person reporting lives abroad, submit within 3 months to the Japanese Embassy or Consulate).

If one or both parents are Japanese nationals (or if an acknowledgement of prenatal paternity [Taiji Ninchi] has already been submitted for a child born between a foreign mother and Japanese father out of wedlock), the child born will have Japanese nationality by birth.
 
However, if a child born abroad also acquires foreign citizenship by birth, a Birth Registration indicating an intention to reserve Japanese nationality must be submitted within 3 months or the child will lose Japanese nationality retroactively from the time of birth (Nationality Law Article 12).
 
Counting from the birthdate, the deadline for the Birth Registration will be one day before they turn 3 months old. For example, the Birth Registration for a child born on April 1^st will have a deadline one day before July 1^st, which is June 30th. July 1^st will be past the deadline, so please submit without delay.
 
If the Birth Registration could not be submitted on time, the child has lost Japanese nationality. However, the child (while still a minor) can live in Japan and apply to acquire Japanese nationality at the Legal Affairs Bureau that has jurisdiction over their residence (Nationality Law Article 17(1)).
 
If the registration could not be submitted within 3 months due to a long-term halt of traffic and mail delivery caused by natural disasters and such and there were no other means to submit the registration, an individual review may determine that the reason is not attributable to the submitter. In such instances, the Birth Registration may be accepted and the Japanese nationality may be recognized.

The Japanese Nationality Law is based on the principle of single nationality, so if you have Japanese and foreign citizenship and became a dual (or more) citizen before age 18, you must choose a nationality by age 20 or if you became a dual citizen after age 18, you must choose a nationality within 2 years (Nationality Law Article 14(1)).
 
To choose Japanese nationality, you have the option to either renounce your foreign citizenship or declare Japanese nationality.
 
If you renounced your foreign citizenship in accordance with the law of that country, attach the renunciation certificate and submit the Foreign Denaturalization Registration to the municipal office, Japanese Embassy or Consulate. For information on renouncing your foreign citizenship, please consult the government, embassy, or consulate of that country.
 
To declare Japanese nationality, you will need to submit a Declaration Registration with intent to “choose Japanese nationality and relinquish foreign citizenship” to the municipal office, Japanese Embassy or Consulate.
 
To declare foreign citizenship, you have the option to either renounce your Japanese nationality or declare foreign citizenship.
 
To renounce your Japanese nationality, you must submit the Renunciation Registration along with all required documents including the Koseki Tohon to submit to the Legal Affairs Bureau, Regional Legal Affairs Bureau, Japanese Embassy or Consulate that has jurisdiction over your residence.
 
If you declared foreign citizenship in accordance with the law of that country, attach the certificate of declaration and submit the Denaturalization Registration to the municipal office, Japanese Embassy or Consulate.
 
Although the Japanese Nationality Law sets a deadline to choose nationality, please keep in mind that you are still obliged to choose even after this deadline. 
 
If you have additional questions, please contact the Consular Section at (213) 617-6700.