Guide 03

My Number, explained

My Number (個人番号) is the twelve-digit number Japan uses for tax, social security and a growing list of everyday procedures.

When you get one

My Numbers are issued to people on Japan's resident register. In practice, that means you receive yours after registering your address at the city or ward office. You can't get one before you've moved in.

The number and the card are different things

The number is assigned automatically. The My Number card is a separate photo ID you apply for, and it's what most online services and many shops mean when they ask for "your My Number card".

Japanese nationals returning from abroad

The My Number system started on 5 October 2015. If you're Japanese but moved abroad before that date and haven't been on a Japanese resident register since, you were never assigned a number.

Since 2024, Japanese nationals living abroad can keep using, or apply for, a My Number card overseas, but only if they already have a number. Having a koseki (family register) or filing a zairyu todoke with your embassy does not count as resident registration.

A short visit home usually isn't enough either: city offices generally treat stays of under about a year as temporary, and registration is meant to reflect where you actually live. If you're moving back for real, you'll be issued a number when you register.