2025-07-07

International marriages are increasing in Japan, but what happens to your family name (surname) after marriage? In Japanese marriages, either the husband or wife must take the surname of the other, but what about international marriages? Let us explain in detail.

International Marriage and Surnames

When a foreign national and a Japanese person marry, the surname of the Japanese person remains the same and the couple is allowed to have separate surnames. On the other hand, under current Japanese law, when two Japanese nationals marry, they must unify their surnames with those of their husbands or spouses.

You may think that it is strange and unfair that only Japanese nationals of international marriages are allowed to have separate surnames. However, there is a fundamental problem with this. It is the “family register.

When two Japanese people marry, either the wife enters the husband’s family register or the husband enters the wife’s family register. In the former case, both spouses take the surname of the husband, and in the latter case, both take the surname of the wife.

However, if a foreigner marries a Japanese national, he or she cannot be registered in the Japanese family register. This is because only Japanese nationals can create a family register or be included in a family register. In other words, in Japan, family registers and surnames are one and the same.

For this reason, “separate surnames” are allowed only in the case of international marriages in Japan. Therefore, if a Japanese couple marries a foreigner, they will take the surname they had before the marriage if they do not follow any procedures.

How to change to the other person’s surname

As explained earlier, in the case of an international marriage in Japan, the couple will take different surnames.

However, there may be couples who wish to take the same surname during their married life. Here, we will consider how to change to the other party’s surname.

First, if a foreign national wishes to have the same surname as his/her Japanese spouse, the man may apply for naturalization and obtain Japanese citizenship. Then, after creating a family register, he can either enter his wife’s family register or his wife can enter his own family register. In this way, he can take the same surname as his wife.

Even without naturalization, you can take the same surname as your Japanese spouse by having a common name (nickname). A common name is a name given by a foreign national who takes the name of a Japanese national, but unlike a mere pseudonym, it can also be listed on the residence certificate and driver’s license. Thus, Ms. XX, who is married to Mr. Sato, can use the name “XX Sato.

In addition, if a Japanese national wishes to take the same surname as his/her foreign spouse, he/she can do so by changing the surname in the family register he/she currently holds to the foreign national’s surname. The procedure is to submit a “Notification of Change of Family Name” at the municipal office, embassy or consulate within 6 months of marriage. After this period, after obtaining permission from the family court, a “Notification of Change of Family Name” should be submitted to the municipal office.

What will happen to the surname of the child?

When a child is born to an internationally married couple, the child will, in principle, take the surname of the Japanese national. This is because if one of the spouses is Japanese, the law states that the child is Japanese, that is, the child has Japanese nationality.

If you wish to change your child’s surname to that of the foreign national, you must file a “petition for change of surname” with the family court and obtain permission.

Summary

In the case of an international marriage, the couple cannot take the same surname unless the foreign national acquires Japanese citizenship. However, the foreign national may use a nickname and take a Japanese surname. In addition, children born from international marriages are basically required to take the surname of a Japanese national.