How to Join National Health Insurance in Japan: Eligibility, 14-Day Deadline, Documents & My Number

National Health Insurance, commonly called NHI or kokumin kenko hoken, is the municipal public medical insurance system for residents who are not covered by another qualifying public medical insurance plan.

The most important first step is to confirm your current insurance status. If an employer is enrolling you in employee health insurance, or if you qualify as another person’s dependent, you generally should not enroll in municipal NHI at the same time.

Foreign-resident eligibility can also depend on residence registration and residence-status conditions. Do not decide from visa length or employment status alone; ask the municipality if your situation is unclear.

• You recently moved to Japan and registered an address but have no other public health insurance.
• You left a job and your employee health insurance ended.
• You stopped qualifying as another person’s dependent.
• You are self-employed, freelance, studying, between jobs or otherwise not covered by employee insurance.
• You moved from another municipality and need to establish NHI coverage in your new municipality.

The Ministry of Health, Labour and Welfare states that people must submit the required notification to their municipality within 14 days when they become insured by NHI or when they leave it.

The 14-day period can start after a move, loss of employee insurance, loss of dependent status or another change that makes you eligible. The effective date of coverage may be earlier than the day you finally visit city hall.

Late filing can create retroactive premiums and extra reimbursement procedures for medical bills paid before your enrollment was processed. If you have already missed the deadline, contact the municipality rather than waiting longer.

• Confirm the exact date your previous insurance ended.
• Keep any certificate showing loss of employee health-insurance eligibility.
• If you recently moved, complete resident-registration procedures as required.
• Ask the municipal office which date it will use as your NHI eligibility start date.

NHI is administered by the municipality where you are registered as a resident, so the office name, counter location, required documents and available online or mail procedures differ by city, ward, town or village.

Before visiting, check the official municipal website. Some municipalities handle NHI at the main city hall, while others also accept procedures at branch offices.

If you recently left a job, proof of the date your employee health insurance ended is especially important because a resignation notice by itself may not be enough to establish the insurance-loss date.

• Residence card or other accepted identity document.
• My Number Card or another accepted document showing your Individual Number, if requested.
• Proof that previous employee or dependent coverage ended, when applicable.
• Documents for family members who are enrolling in the same household.
• Bank-account information if you want to set up automatic premium payment and the municipality supports it.
• Any additional document listed by your municipality for your specific reason for enrollment.

At the counter, explain why you need to join NHI and provide the date your previous coverage ended or the date you became a resident in the municipality. The staff will check eligibility, household information and the documents required for your case.

Before leaving, confirm the effective date of NHI coverage, who in the household is enrolled, what proof of eligibility you should use, when premium notices will arrive and whether any additional document must be submitted later.

Do not assume that resident registration automatically completes NHI enrollment. The procedures are related but separate.

• Confirm your eligibility start date.
• Confirm which household members are enrolled.
• Ask when the first premium notice will be sent.
• Ask how to pay and how to change the payment method later.
• Ask what procedure is required if you start a new job, move or leave Japan.

There is no single nationwide NHI premium. Municipalities calculate premiums or insurance taxes under local rules, so the amount can differ even for households with similar income.

The calculation commonly uses previous-year income, the number and ages of insured household members and annual municipal rates. For members aged 40 to 64, the premium can also include a long-term-care insurance component.

Premium notices are usually managed at household level. Even if the head of household is not personally enrolled, notices may still be addressed to that person under municipal rules.

Payment methods differ by municipality and can include payment slips, convenience-store payment, bank transfer, automatic withdrawal and approved online or smartphone methods.

• Check the annual premium decision notice rather than estimating from another city’s rates.
• If you recently arrived in Japan, ask whether an income declaration is required even if you had no Japanese income in the previous year.
• Keep receipts or digital payment records until the municipality reflects the payment.
• Contact the municipality early if a premium notice appears incorrect.

NHI covers approved medically necessary treatment under Japan’s public medical insurance rules. Most working-age adults generally pay 30 percent of the approved cost at the point of care, while different statutory percentages apply for some age and income groups.

Not every service is covered. Cosmetic treatment, some health checks, optional private-room charges, some vaccinations and other non-insured services may be charged separately.

If covered medical expenses become very high, Japan’s High-Cost Medical Expense Benefit can limit the patient’s burden according to age, income and other conditions. The system was revised from August 2026, so use current MHLW information or ask your municipality before expensive planned treatment.

• Bring your My Number Insurance Card or valid eligibility confirmation document.
• Ask whether a treatment or optional service is covered before agreeing to a large charge.
• Keep receipts when you pay the full amount because your eligibility could not be confirmed.
• For planned hospitalization or expensive care, check the current high-cost medical expense rules in advance.

Ignoring premium notices can lead to reminders, late charges and collection procedures. If payment is difficult, contact the municipal NHI office before the due date.

Depending on your income, job-loss circumstances, disaster impact or other local conditions, reductions, exemptions, special calculations or payment consultation may be available. Eligibility and required evidence vary by municipality.

A low or zero income does not automatically mean the premium is zero. The municipality may need an income declaration before it can apply an income-based reduction.

• Bring recent income or job-loss documents if requested.
• Ask whether an installment arrangement or reduction program applies.
• Do not skip notices because you are waiting for another procedure to finish.
• Keep written confirmation of any approved payment arrangement.

NHI does not always stop automatically when another insurance system starts. If you join employee health insurance, notify the municipality and complete the NHI withdrawal procedure within the required period.

When moving to another municipality, you generally leave NHI in the old municipality and complete the appropriate enrollment procedure in the new one. Premium rates and payment schedules can change after the move.

Before leaving Japan, complete the required moving-out and NHI procedures and confirm any final premium balance or refund. Also report household changes that affect insurance eligibility.

• Starting employee insurance: confirm the new start date and withdraw from NHI.
• Leaving employee insurance: compare NHI, voluntary continuation and dependent coverage without missing their separate deadlines.
• Moving municipality: complete old-municipality and new-municipality procedures.
• Leaving Japan: complete moving-out and NHI withdrawal procedures before departure where possible.
• Family changes: report births, deaths, moves and changes in dependent or employee-insurance status.