City Hall Procedures: MyNumber and National Insurance Setup for Residents

When you move to Japan and register your address at the city hall, one of the most important administrative steps you’ll encounter is related to MyNumber (マイナンバー) and National Health Insurance (国民健康保険). These two systems are essential for both residents and long-term visitors in Japan. This guide explains what they are, how to register, what documents to bring, and what to expect during your visit to the city office.

Understanding the MyNumber System

The MyNumber system, officially called the Social Security and Tax Number System, assigns a unique 12-digit number to every resident of Japan. This number is used to manage taxes, social security, and disaster response more efficiently.

Who Receives a MyNumber

All residents who are registered with a local municipality—including both Japanese citizens and foreign residents with a mid- to long-term visa—are automatically assigned a MyNumber. Short-term visitors or tourists do not receive one.

Purpose of MyNumber

The MyNumber is used primarily for:

  • Income tax and social security management

  • Health insurance and pension registration

  • Employment and payroll reporting

  • Public welfare and benefits applications

It helps simplify procedures between government offices and ensures that personal data is managed consistently across systems.

How to Receive Your MyNumber Notification

Once you register your address at the city hall or ward office, your MyNumber notification card will be mailed to you within a few weeks. This letter contains your 12-digit number and instructions on how to apply for a MyNumber Card (マイナンバーカード), which serves as an official photo ID.

Applying for the MyNumber Card

To apply for the MyNumber Card, you can:

  1. Use the QR code on your notification letter to apply online.

  2. Submit the included form by post.

  3. Apply directly at the city office.

You’ll need:

  • The notification letter or your Residence Card

  • A recent photo (taken within the past six months)

  • Your signature or seal (if requested)

The card takes about 4–6 weeks to be issued. You’ll receive a postcard notifying you to pick it up at the city office.

Benefits of Having a MyNumber Card

Although optional, the MyNumber Card is highly useful in daily life. It functions as:

  • An official ID card with your photo and IC chip

  • A health insurance card (for clinics and hospitals)

  • A convenient online identity for government services (via MynaPortal)

  • A library card or resident certificate card in some municipalities

Having a MyNumber Card makes many administrative processes—such as tax filing or pension applications—much faster and easier.

Registering for National Health Insurance

After registering your residence, foreign residents who are not covered by employer-based insurance must enroll in National Health Insurance (Kokumin Kenkō Hoken). This system ensures that everyone in Japan has access to affordable medical care.

Who Should Join

You must join if:

  • You are a resident of Japan with a visa longer than three months

  • You are not covered by your employer’s health insurance

  • You are self-employed, a student, or unemployed

If you start working full-time later, your company’s health insurance will replace the National Health Insurance.

How to Enroll at City Hall

Enrollment is done in person at your local city or ward office—usually in the insurance section.

Documents You’ll Need

  • Residence Card (在留カード)

  • Passport

  • MyNumber (notification or card)

  • Residence certificate (住民票) if already issued

  • Proof of income (if applicable, from the previous year)

After submission, you will receive a Health Insurance Card (保険証)—either immediately or by mail in about a week.

Health Insurance Premiums

Your insurance premium (保険料) is based on your previous year’s income, number of dependents, and municipality. For newcomers with no prior income in Japan, premiums start at a low base rate, but they can increase after your first year.

You can pay your premiums:

  • Monthly at convenience stores

  • By automatic bank transfer

  • Quarterly billing options (depending on your city)

Failing to pay may result in limited benefits or difficulties renewing your visa, so it’s important to stay up to date.

What the Insurance Covers

National Health Insurance covers about 70% of your medical expenses. You pay only the remaining 30% at the hospital or clinic. The system applies to:

  • Doctor visits and hospital stays

  • Prescriptions and treatments

  • Dental care (basic procedures)

  • Childbirth-related benefits (partial reimbursement)

High-cost medical expenses can be partially reimbursed if your out-of-pocket payments exceed certain thresholds.

Combining MyNumber and Health Insurance

Since 2023, Japan has been gradually integrating MyNumber Cards and health insurance cards into a single ID. By linking them, you can use your MyNumber Card at hospitals, clinics, and pharmacies.

Benefits of Linking

  • Simplifies medical registration

  • Enables access to your medical history and prescriptions online

  • Reduces the need to carry multiple cards

How to Link

You can register your MyNumber Card as a health insurance card:

  • Online through the MynaPortal app

  • At convenience stores with “MyNumber Card Reader” terminals

  • At your local city office counter

What to Do If You Move to Another City

If you change your address, you must:

  1. Notify your current city hall before moving out.

  2. Re-register your residence and MyNumber at the new city office.

  3. Update or transfer your National Health Insurance enrollment.

Failure to re-register within 14 days may result in loss of coverage or penalties.

Lost or Damaged MyNumber Card

If you lose your MyNumber Card, contact the city office or MyNumber Call Center immediately. The card will be suspended to prevent misuse, and you can apply for a replacement by submitting an ID and completing a form at the city office.

For foreigners leaving Japan permanently, you must return your MyNumber Card to the municipal office before departure.

Frequently Asked Questions

Q1: Do I need to apply separately for MyNumber after moving to Japan?
No. Your MyNumber is automatically issued when you register your address at the city office.

Q2: How long does it take to get the MyNumber Card?
Typically about 4–6 weeks after application. You’ll be notified when it’s ready for pickup.

Q3: Can I refuse to join National Health Insurance?
Only if you’re already covered by employer-based or private health insurance recognized by Japan. Otherwise, it’s mandatory.

Q4: What happens if I don’t pay insurance premiums?
Unpaid premiums can result in reduced medical coverage and problems during visa renewal.

Q5: Can tourists apply for MyNumber or National Health Insurance?
No. Both systems are available only to residents with a visa valid for more than three months.

Q6: Can family members share one MyNumber?
No. Each resident—including children—receives their own unique 12-digit MyNumber.

Q7: What should I do if I move to another city in Japan?
You must cancel insurance in your old city and register again in your new city within 14 days.

Conclusion

Setting up your MyNumber and National Health Insurance is one of the first and most important administrative tasks when living in Japan. These systems ensure that residents can access essential health services and manage taxes or social benefits smoothly. While the process may seem bureaucratic at first, Japan’s city halls are generally efficient and provide English-language support in major municipalities. Once you complete these steps, you’ll be officially integrated into Japan’s public systems—ready to enjoy daily life with peace of mind.

FAQs

What is MyNumber and who receives it?

MyNumber is Japan’s 12-digit Social Security and Tax Number used for taxation, social security, and certain administrative services (including disaster response). Every resident registered with a municipality—including foreign residents with mid- to long-term visas—receives a MyNumber. Short-term visitors and tourists do not receive MyNumber.

Do I need to apply for a MyNumber, or is it automatic?

It is automatic. After you file your moving-in (address) registration at your city or ward office, the municipality generates your MyNumber and sends a notification document to your registered address. No separate application for the number itself is required. However, applying for the physical MyNumber Card (photo ID) is optional and requires action from you.

What is the difference between the MyNumber notification and the MyNumber Card?

The notification is a letter informing you of your 12-digit number. The MyNumber Card (with IC chip and photo) is a government-issued ID you apply for. The card allows online identity verification, access to digital government services (via the MynaPortal), and can be used as a health insurance card in integrated systems. The notification alone is not a valid photo ID.

How do I apply for the MyNumber Card?

You can apply online using the QR code in the notification letter, by mail with the enclosed form, or in person at your city office. Typical requirements include your notification letter or residence card number, a compliant ID photo taken within the last six months, and in some cases a signature or seal. Processing commonly takes several weeks; you’ll receive a pickup notice postcard when it is ready.

What are the benefits of having a MyNumber Card?

Key benefits include: (1) valid government photo ID for many procedures, (2) use as a health insurance card at medical facilities that support card readers, (3) streamlined access to e-government services (tax filings, benefits, certificates) via MynaPortal, and (4) optional local services like library card functionality in some municipalities. While not mandatory, it significantly simplifies procedures.

Is it safe to share my MyNumber with employers or institutions?

Only share your MyNumber when there is a clear legal basis—such as payroll tax reporting, social insurance procedures, or government benefit applications. Companies and agencies must follow strict handling rules. Avoid sharing it casually, and never post it online. If a private company requests it, you may ask which statutory process requires the number and how they will safeguard it.

What should I do if I lose my MyNumber Card or suspect misuse?

Immediately contact the MyNumber Call Center or your city office to suspend the card. Then apply for a reissue in person with the required identity documents. If you suspect fraud, also consult the police and keep records of calls and notifications. While the card can be reissued, limiting exposure quickly is crucial.

Who must enroll in National Health Insurance (Kokumin Kenkō Hoken)?

Residents not covered by employer-sponsored health insurance must enroll, including self-employed workers, students, part-time workers without company coverage, and dependents who are not included in a company plan. If you later join a company plan, you must notify the city office to withdraw from National Health Insurance to avoid double coverage and duplicate bills.

When and where do I enroll in National Health Insurance?

Enroll at the insurance counter of your city or ward office promptly after moving in (generally within 14 days of establishing residency). Bring your residence card, passport, MyNumber (notification or card), residence certificate if issued, and any relevant insurance certificates or proof of loss of prior coverage. The office may issue a temporary paper card or mail your plastic health insurance card shortly after.

How are National Health Insurance premiums calculated?

Premiums vary by municipality and are based on prior-year income, household composition, and a per-capita/household portion. Newcomers with no reported prior-year Japan income usually pay closer to the minimum, though municipal rules differ. Bills are typically payable by convenience store slips, direct debit, or bank transfer. Missing payments can result in reduced benefits and potential issues with immigration procedures.

What does National Health Insurance cover, and how much do I pay at the clinic?

Standard medical fees are cost-shared: the insurer pays roughly 70%, and you generally pay 30% at the point of service (co-payment percentages can vary by age or program). Covered services include visits, hospitalization, many prescriptions, and basic dental. For exceptionally high monthly out-of-pocket costs, a high-cost medical expense system may reimburse part of the excess, subject to application and limits.

How do I link my MyNumber Card to my health insurance?

Many municipalities and insurers support MyNumber–health insurance integration. You can register via MynaPortal, at participating convenience stores with readers, or directly at your city office or certain medical facilities. Once linked, your MyNumber Card can be presented as your health card at hospitals and pharmacies that support the system, speeding up check-in and enabling digital record access features.

What if I move to another city or change employers?

If you move, file a moving-out notice in your old city and a moving-in notice in your new city, then transfer or re-enroll your health insurance as appropriate. If you switch to employer-sponsored insurance, enroll through your employer and promptly disenroll from National Health Insurance at the city office. Always update your address for MyNumber records to ensure mail and notices reach you.

Can family members share coverage or MyNumber?

No. Each person has a unique MyNumber. For health insurance, household members can be covered within the same National Health Insurance household account, but each person has their own personal health insurance card and co-payment obligations. In employer plans, dependents may be covered if they meet criteria; otherwise, they must enroll separately.

Do international students and dependents need to enroll?

Yes, if they are residents for more than three months and not covered by an employer plan. Students should enroll soon after moving in to avoid gaps in coverage. Premiums for low-income students are often modest, and some municipalities provide partial reductions; inquire at your city office about possible relief if your income is limited.

What documents should I bring to city hall for MyNumber and insurance procedures?

Commonly requested items include your residence card, passport, proof of address (or jūminhyō if already issued), MyNumber notification or card (if applicable), proof of prior insurance termination or employer coverage, and bank details if setting up direct debit. Bring recent ID photos if applying for the MyNumber Card in person. Requirements can vary slightly by municipality.

How long does the MyNumber Card issuance take, and how do I collect it?

Processing typically takes several weeks. The city office will mail a pickup postcard with instructions and required items (such as your notification letter, residence card, and the postcard itself). Collection is usually in person, and you may need to set PINs for the card’s digital certificates during pickup. If you cannot go in person, check your city’s rules for proxy pickup or alternate arrangements.

What happens if I forget to enroll or pay National Health Insurance?

Delays in enrollment can lead to retroactive billing from your move-in date, and unpaid premiums can accumulate late fees or cause benefit restrictions. Medical providers may still treat you, but you could face higher out-of-pocket costs and complex reimbursement steps. Always enroll and pay on time to avoid administrative and financial complications.

Can I use private international insurance instead of National Health Insurance?

Private plans do not generally exempt residents from mandatory enrollment if they lack employer coverage. Some employer or treaty situations may differ, but for most residents, National Health Insurance (or employer insurance) is required. You may keep private insurance as supplemental coverage for services not fully covered domestically or for international travel, but confirm details with your city office.

How do I access digital services with MyNumber (MynaPortal)?

With a MyNumber Card and set PINs, you can log into MynaPortal via compatible card readers or smartphone NFC. Available services can include viewing certain personal records, applying for benefits, retrieving tax data, downloading certificates, and checking your health insurance eligibility or medical fee records where supported. Keep your PINs secure and update them if compromised.

What should I do before leaving Japan permanently?

File a moving-out (departure) notice at your city office, settle all National Health Insurance premiums, and disenroll from the system. Return your MyNumber Card to the city office when completing departure formalities. Keep receipts and final statements, as you may need them for tax or refund inquiries after you leave.

Are there language support options at city hall?

Major wards and cities often provide English materials and, in some cases, interpretation or multilingual counters. Smaller municipalities may rely on printed guides or simple English forms. If you anticipate language barriers, bring a Japanese-speaking friend, arrange an interpreter, or prepare translated documents and key phrases to streamline your visit.

How can I minimize time at city hall and avoid mistakes?

Prepare a checklist: (1) confirm your appointment (if offered), (2) bring all identification and address documents, (3) have ID photos ready for the MyNumber Card, (4) bring bank details for premium payments, and (5) carry prior insurance documents. Arriving early, using online pre-applications where available, and double-checking forms before submission will help ensure a smooth experience.

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