This one confuses almost everyone, because two different things share a name. Mio separates them cleanly: the number (you already have it) versus the card (a choice). Here's the read from the official Japanese sources, in English.
The My Number is a 12-digit individual number assigned to everyone with a residence record in Japan — Japanese citizens and foreign residents alike. If you hold a residence card and have completed your move-in registration at your local municipality, a My Number has been assigned to you. It's used for legally defined procedures in social security, taxation, and disaster response.
The My Number Card is a separate, optional IC (chip) card you can apply for. It physically shows your name, address, date of birth, and gender, carries your My Number, and holds a digital certificate (JPKI) that lets you authenticate online. You can live in Japan without ever getting the card — but several conveniences are gated behind it.
| Use | What it gives you |
|---|---|
| Photo ID | A government-issued photo ID card, useful when you don't want to carry your passport. |
| Tax (e-Tax) | File your income-tax return online and authenticate with the card's digital certificate, instead of paper. |
| Health insurance | Can be linked to your public health insurance (the "Myna" insurance-card system) and scanned at clinic/hospital reception. Confirm your own setup — see caution below. |
| Certificates | Print official documents (e.g. residence certificate) at convenience-store kiosks in many municipalities, instead of queuing at city hall. |
| Employment / banking | Employers and some financial procedures ask for your My Number; the card is a convenient single document that proves both number and identity. |
Exact services vary by municipality and by insurer, and the rules are changing. Treat the list as "commonly available," not guaranteed for your city — verify locally.
Japan has been shifting public health insurance onto the My Number Card. When linked, you scan the card at the reception terminal instead of showing a separate insurance card. Two things to keep in mind as a foreign resident:
First, you can still receive insured medical care without the card — people without a My Number Card are generally issued an alternative certificate confirming enrolment. Second, enrolment in health insurance and getting the card are separate steps; the card typically takes several weeks to arrive, so you'll usually have interim proof of coverage. Because timing and procedures differ by insurer and municipality, confirm the exact method with your city office or insurer rather than assuming.
It expires with your visa. For foreign residents, the card's validity is generally tied to your period of stay. When you renew your residence status, you typically have to update the card at the city office too — an extra errand at renewal time.
Application takes weeks. Producing the card commonly takes several weeks after you apply, so it's not an instant on-arrival ID.
It's a sensitive document. The card links to tax and administrative data, so losing it means calling the freeze line and replacing it. If you'll leave Japan soon or rarely file taxes, the payoff is smaller.
Note: in June 2026 Japan introduced an option to combine the residence card and My Number Card into a single "Specified Residence Card." Availability and details are still rolling out — check the official pages below for your situation.
You don't apply for the number — it's assigned when you register your address. To get the card, you use the application code/QR on the notification you received, and apply online, by smartphone, by mail, or at your municipal (city/ward) office. After processing (several weeks), you collect the finished card in person at city hall, usually with an appointment and your residence card. The official portal below has the current step-by-step in English.
Staying long-term, working, or filing taxes → get the card. The e-Tax, ID, and insurance-linkage payoff is real. Short stay, rarely dealing with tax or clinics → the number alone is often enough, and you can decide on the card later. Just don't confuse the two: the number is already yours; the card is the upgrade.