Guides · 保険加入 · hoken kanyū
Joining Japanese Health Insurance — The 14-Day Rule and What You'll Pay
If you live in Japan on a visa longer than three months, enrolment in public health insurance is not optional — and, unusually for a compulsory system, it is a genuinely good deal. This guide covers how you get in, what it costs, and the traps.
Which system you belong to (you don't choose)
There are two doors, and your employment status decides which one is yours.
Employee Health Insurance (健康保険, kenkō hoken / "Shakai Hoken") — if you work for a company roughly 20+ hours a week, your employer must enrol you. Everything is handled through payroll: the premium is deducted from salary, your employer pays half, and enrolment happens with your first paycheck. You receive your insurance credentials without visiting any office. If this is you, your only real task is to confirm it happened.
National Health Insurance (国民健康保険, kokumin kenkō hoken / "NHI") — for everyone else: freelancers, language students, business owners, part-timers under the threshold, the unemployed, and dependents of NHI members. Enrolment is your responsibility, at the city office, within 14 days of taking up residence (or leaving an employer's scheme).
Both systems buy the same medical care: 30% co-pay, the same high-cost expense cap, the same childbirth lump sum. The differences are in premiums and dependents.
What it costs
Employee insurance: roughly 10% of salary for health insurance (plus pension, separately), but you pay only half — about 5% of gross salary, pre-deducted. Simple.
NHI premiums are calculated from your previous year's income in Japan. This single fact explains most of the surprises people experience:
- Your first year in Japan is cheap — you had no Japanese income last year, so you pay close to the minimum, typically ¥20,000–90,000 per year depending on the municipality.
- Your second year can jump sharply — now it reflects your first year's earnings. Freelancers hit by the "year two shock" have usually just forgotten this. Set money aside.
- Premiums vary noticeably by municipality, and are capped (the annual ceiling is around ¥1.1 million for high earners).
If your income falls — you lose work, your business shrinks — NHI has reduction and exemption programs (減免), but they are applied for, not automatic. If a premium bill is genuinely beyond you, go to the city office counter and say so before skipping payments; unpaid premiums can be back-billed up to two years when you eventually enrol, so "I'll join when I'm sick" is a strategy that costs more, not less.
Dependents: the big structural difference
Employee insurance covers dependents (扶養) at no extra premium — a non-working spouse and children ride on one worker's enrolment for free, subject to income limits (a dependent must earn under roughly ¥1.3 million/year).
NHI has no dependent concept — every household member is a member, and the household premium is the sum of its parts. A family of four on NHI pays more than a family of four on employee insurance, sometimes much more. This is one reason a job offer with 社会保険完備 ("full social insurance") is worth real money beyond the salary line.
Your proof of insurance
Japan has shifted to the My Number card as the standard health-insurance credential (マイナ保険証). Register the linkage once — at a pharmacy terminal, via the Mynaportal app, or at a convenience-store kiosk — and clinics can verify your coverage electronically, including your high-cost cap bracket, which spares you a paper certificate before big treatments. If you do not have a My Number card, insurers issue a paper eligibility confirmation certificate (資格確認書) that works like the old insurance card. Either way, carry your credential to every clinic visit; without it you pay 100% and claim back later.
Common situations, quickly
- Changing jobs: your old employee insurance ends on your last day. If the next job starts immediately, the new employer takes over. If there is a gap of even a week, you must bridge it — either NHI at the city office or voluntary continuation (任意継続) of the old plan for up to two years. An uncovered gap plus one appendicitis is a seven-figure yen mistake; bridge the gap.
- Students: NHI, at the city office, and yes it applies to you even on a student budget — apply for the student reduction.
- Leaving Japan for good: de-enrol at the city office when you file your moving-out notice, and settle the final prorated bill. NHI premiums do not stop by themselves just because you flew home.
- Travel and family visits from abroad: parents visiting you on a tourist stay are not covered by your insurance — they need travel insurance from home. Residency, not family relation, is what enrols a person.
General information, not individual advice — municipal premiums, thresholds and procedures vary and change each fiscal year. Your city office's NHI counter (many have interpretation service) is the authoritative source for your own numbers.