2025-10-18

Recently, more Japanese citizens have been marrying foreign nationals. In such international marriages, what happens to each partner’s nationality? Can one change their nationality upon marriage?

International Marriage and Nationality

When a Japanese national marries a foreign national, neither party’s nationality generally changes. The Japanese national retains Japanese nationality, and the foreign national retains their own nationality.

However, if a Japanese woman marries a man from countries such as Saudi Arabia, Iran, or Ethiopia, the Japanese woman is automatically granted the nationality of the man’s country. Therefore, Japanese women marrying men from these countries should be aware of this.

When a Japanese National Changes Nationality

Even when a Japanese national marries a foreign national, they generally retain Japanese nationality. However, if they acquire the nationality of their spouse’s country upon marriage, they must complete “nationality acquisition procedures” alongside the marriage registration.

Note that the conditions and procedures for acquiring nationality vary significantly by country. It is necessary to inquire at the relevant embassy or consulate in Japan. Some countries impose strict requirements, such as minimum years of residence or income levels, while others require only proof of marriage. The conditions are highly diverse.

Furthermore, Japan does not recognize dual nationality. Therefore, if a Japanese national voluntarily acquires the nationality of their spouse’s country, they will lose their Japanese nationality. Within three months of becoming aware of this loss of nationality, they must submit a “Declaration of Loss of Nationality” to a Japanese embassy or consulate abroad or to their local municipal office.

Note that even if the “Declaration of Loss of Nationality” is not submitted, Japanese nationality is lost at the moment the foreign nationality is voluntarily acquired. It is important to note that if you knowingly use a Japanese passport while having lost Japanese nationality, you may face penalties.

When a Foreign National Changes Nationality

A foreign national married to a Japanese citizen who wishes to change to Japanese nationality through marriage must apply for naturalization at the Immigration Services Agency. Numerous conditions must be met for naturalization (acquisition of Japanese nationality) to be granted.

One of these is the requirement to have resided continuously in Japan for at least five years prior to applying. This is called the “residence requirement.”

For foreign nationals married to Japanese citizens applying for naturalization, the residence requirement is relaxed. Specifically, they must meet one of the following conditions:
① Have maintained a residence in Japan for at least three consecutive years and currently have a residence in Japan, OR
② Have been married for at least three years and have maintained a residence in Japan for at least one consecutive year since the marriage date.

Other requirements include having the financial means to maintain a stable life in Japan (livelihood requirement) and having no criminal record or similar penalties (good conduct requirement).

Summary

Marrying an international partner does not fundamentally change your existing nationality. However, if you choose to acquire your spouse’s nationality upon marriage, specific procedures become necessary.