Japanese Dual Citizenship in the U.S. — 2026 Guide

Japan does not accept dual nationality as a permanent status. Two rules do the work. An adult who voluntarily acquires another nationality loses Japanese nationality automatically, and someone who holds two nationalities from birth must eventually choose one.

Quick facts

Naturalising as a U.S. citizen therefore ends Japanese nationality at that moment, and the person is required to file a report of loss of nationality as soon as possible. A Japanese passport cannot be issued afterwards.

How the rules apply

The consequences follow the fact, not the paperwork: the loss happens on naturalisation whether or not the report is filed, and the report simply brings the register up to date.

What to do in practice

1. For a newborn, file the birth notification with the nationality reservation inside the three-month window. This is the step that preserves everything else.
2. Keep the family register details to hand, since every filing needs the registered domicile.
3. For a dual national approaching the age limit, understand that a declaration of choice is required and what each option means.
4. For anyone about to naturalise in the United States, understand that the Japanese passport becomes unusable from that date.
5. File the report of loss of nationality at the post covering your address, without an appointment where the post allows it.
6. Travel to Japan afterwards on the U.S. passport, with a visa or visa-free entry as applicable.

Required documents

• Japanese passport, current or expired.
• Naturalisation certificate for a report of loss.
• U.S. birth certificate and translation for a birth notification.
• Registered domicile and head of the family register.
• Proof of address in the consular district.
• Completed notification or declaration forms.

Where to file

At the embassy or the consulate general covering your address. Some posts take these filings without an appointment, though the file cannot be sent by mail.

Additional notes

The three-month rule again

Almost every difficult case in this area starts with a birth that was not notified in time. There is no fee and no complexity to the filing itself, only the deadline.

Choosing is a formal act

The declaration of choice is a specific filing, not something that happens by default when a passport expires.

Permanent residence is different

Holding a U.S. green card does not affect Japanese nationality. Only acquiring another nationality does.

Get advice on complex cases

Adoption, assisted reproduction and long gaps in filing produce outcomes that consular staff can describe but not resolve at the counter.