International graduate students residing in Japan for three months or longer are required by law to enroll in the National Health Insurance (NHI) system, commonly known as Kokuho. Once registered, this public insurance program covers 70% of standard medical expenses, requiring you to pay only the remaining 30% out of pocket. By declaring your income at your local municipal office—even as a new student with zero or minimal previous earnings in Japan—you can qualify for substantial reductions on your monthly premium payments.
According to official guidelines published by Study in Japan, understanding how NHI works alongside university-level supplemental policies is essential for managing your healthcare and living expenses throughout your studies.
Who needs to enroll in Japan's National Health Insurance?
Every foreign resident staying in Japan for three months or more must subscribe to the National Health Insurance scheme. This requirement applies to all international graduate students, including research students, master's degree candidates, doctoral candidates, and recipients of Japanese government scholarships such as the MEXT research scholarship.
If your period of stay equals or exceeds three months, enrollment is compulsory rather than optional. Always confirm your specific visa status and residency duration details with official administrative sources or your local municipal government.
How do international graduate students register for NHI?
Registration for National Health Insurance is handled locally through the municipal office responsible for your neighborhood. The process follows a clear administrative order:
- Complete resident registration: Upon arriving in Japan, you must first register your local address at your city or ward office.
- Submit your NHI application: Immediately after completing your resident registration at the same municipal office, apply for National Health Insurance enrollment.
- Receive your health insurance card: Once registered, you will receive a personal health insurance card, which you must bring to all medical appointments to receive standard co-payment discounts.
How are NHI monthly premiums calculated and reduced?
Your National Health Insurance premium is calculated based on your reported income from the previous calendar year in Japan, including any earnings from part-time work. Because calculations depend directly on official records, you must report your income at the municipal office every year.
How does the premium reduction work for students?
- Declaration requirement: If your income falls below a designated threshold, your insurance premiums are automatically reduced.
- Reporting low or zero income: Even if you earned zero income or very little money during the previous year, you must still submit an official income declaration.
- Consequences of failing to declare: Without an official declaration, municipal authorities cannot apply the reduced rate, resulting in significantly higher premium bills than necessary.
What medical coverage does National Health Insurance provide?
When you visit a medical facility in Japan for illness or injury, presenting your valid insurance card entitles you to immediate billing discounts:
- 70% covered by NHI: The public insurance system covers 70% of total eligible medical expenses.
- 30% patient co-payment: You pay the remaining 30% of the bill at the medical clinic or hospital counter.
- Full payment for non-covered items: Any treatments or medical items not recognized under standard public health insurance coverage must be paid in full (100%) by the patient.
What options exist for high medical expenses and hospitalization?
To prevent unexpected illness or injury from causing severe financial distress, the National Health Insurance program includes special protections for high monthly medical bills.
Refunds for high monthly costs
If your total co-payments within a single calendar month exceed your personal financial threshold, you can apply for a partial refund of the excess expenses through your municipal office.
Ceiling certificates for hospitalization
If you face hospital admission or anticipated high medical costs, you can apply in advance for an eligibility certificate. Presenting this certificate at the hospital limits your out-of-pocket payment directly to your personal monthly cap, eliminating the need to pay large sums upfront.
Why should international students get supplemental insurance?
While National Health Insurance provides strong medical coverage, it does not cover personal liability, property damage, or non-medical accidents. Schools across Japan recommend combining NHI with specialized student insurance policies.
Student accident coverage (Gakkensai)
Most universities, graduate schools, junior colleges, and technical colleges adopt Personal Accident Insurance for Students Pursuing Education and Research, known as Gakkensai. Offered through Japan Educational Exchanges and Services, this policy covers injuries sustained during academic classes, research activities, and daily commutes between home and campus. International students can also add "Inbound Futai-Gakuso" to complement their Gakkensai coverage. Because availability varies by institution, check with your graduate school office to confirm details.
University CO-OP Kyosai
Many universities offer a mutual aid insurance system called University CO-OP's Kyosai, which students can join during their enrollment to cover various everyday risks.
Personal liability and property insurance
Standard NHI does not protect against third-party damages or property loss. Supplemental casualty or liability plans protect against incidents such as:
- Kitchen fires: Accidental cooking oil fires that burn kitchen walls and require structural repair.
- Bicycle accidents: Colliding with and injuring a pedestrian while riding a bicycle, resulting in costly personal injury liabilities.
- Theft: Burglary of your residence while you are away, resulting in stolen personal belongings such as computers or cameras.
Finding a place to stay
When preparing to move to Japan for graduate studies, organizing your accommodation timeline is key. Most international students arrange their initial housing after their Certificate of Eligibility or visa is issued, but before landing in Tokyo. Upon arrival, many newcomers stay in a furnished monthly apartment first to complete municipal procedures—such as resident registration and health insurance enrollment—before settling into long-term living arrangements.
OHAYO Stay offers furnished monthly apartments and rooms in Tokyo. Booking is completed online with a passport or ID and a credit card, requiring no guarantor, no key money, and no agency fee. Groups, longer stays, and students can ask for a quote; a special price is often possible.
FAQ
Is National Health Insurance mandatory for international graduate students in Japan?
Yes, any foreign resident staying in Japan for three months or longer must subscribe to National Health Insurance at their local municipal office.
What percentage of medical costs does Japan's National Health Insurance cover?
National Health Insurance covers 70% of eligible medical costs, leaving the patient to pay 30% of the bill for covered treatments.
How can new graduate students lower their monthly insurance premiums?
Students must declare their income at the local municipal office every year; even with zero or low previous income, declaring status unlocks automatic premium reductions.
Sources
- Study in Japan(JASSO)「Insurance｜Study in Japan Official Website」(checked 2026-10-13)
This article was created by OHAYO Stay based on the sources above (edited, reorganized and translated). It is not an official publication.
Rules and dates can change. Always confirm with the official source before you apply.