National Health Insurance (NHI / Kokuho)

What NHI is and who it covers

National Health Insurance (国民健康保険, Kokumin Kenkō Hoken — often called NHI, Kokuho, or kokuhoken) is the residual public insurance scheme in Japan’s universal system. It covers any resident not enrolled in an employment-based insurance scheme through their workplace. This includes self-employed workers, students, unemployed residents between jobs, part-time workers whose employers do not provide shakai hoken, and retired individuals under 75.

Foreign residents are subject to the same enrollment rules as Japanese nationals. Once you complete residence registration at your municipal office and your residence period exceeds three months, you are required to enroll. This applies regardless of nationality.

How to enroll

Enrollment is done in person at your municipal office’s health insurance or citizens affairs counter (国保係, kokuhogakari). Bring your residence card (在留カード, zairyū kādo), your residence registration printout (住民票, jūminhyo), and your passport. If you are moving from another municipality, bring your withdrawal certificate from the previous municipality’s NHI and your new residence registration.

The office will issue your insurance card (保険証, hokenshō) on the spot or by mail within a few days. The card lists your name, the effective date, the insurance fund name, and a unique member number. Present it at every medical appointment to receive the standard 70% coverage on eligible services.

Understanding your premiums

NHI premiums are calculated at the household level (世帯, setai) — all household members enrolled in NHI are billed as a single unit, with the head of household responsible for payment. The premium has two components: an income-proportional portion based on the previous year’s income for each household member, and a flat-rate portion (均等割, kintōwari) charged per enrolled member. Some municipalities also charge a property-based component.

Total premiums vary considerably between municipalities. Urban ward offices often publish calculators on their websites. First-year residents who have no prior Japanese income history typically see a lower premium, as the income base defaults to zero. From the second year, premiums reflect the previous year’s declared income.

Premiums are typically paid in installments across the fiscal year (April to March), billed by the municipal office. Payments can be made at convenience stores, banks, post offices, or set up as direct bank debit (口座振替, kōza furikae).

Late enrollment and gaps in coverage

Enrollment is legally mandatory from the date you become eligible. A gap between eligibility and enrollment does not eliminate the liability for premiums — the municipal office will typically back-bill to the date of residence registration. However, you will not be able to claim retroactive insurance benefits (the 70% coverage) for medical expenses incurred during a period when you were not formally enrolled.

If you had a genuine period without coverage — for example, you were covered by employer insurance, that insurance lapsed, and there was a gap before NHI enrollment — document the dates carefully and discuss the situation with the municipal counter. The procedures for retroactive billing and retroactive benefit claims are separate processes.

What the card covers

Your NHI card covers 70% of the standardized national fee schedule for outpatient visits, inpatient stays, diagnostic testing, most surgical procedures, and medications dispensed under a prescription. The 30% copayment you pay at the clinic or pharmacy is your share.

Children under 18 are typically subject to different copayment rates or additional subsidies managed at the prefectural or municipal level. Residents aged 70 to 74 pay a 20% copayment on most services; those 75 and over transition to a separate scheme called Latter-Stage Elderly Medical Insurance (後期高齢者医療, kōki kōreisha iryō).

Withdrawing from NHI

When you start a job that enrolls you in shakai hoken, you must formally withdraw from NHI within 14 days. Bring your NHI card and the new shakai hoken enrollment certificate to the municipal office. Failure to withdraw can result in duplicate premium billing. If you lose your NHI card, request a replacement at the municipal office.

Last reviewed: September 2026