Health Insurance After You Quit Your Job in Japan

The short version

Your company health insurance ends the day after your retirement date, with no grace period and nothing continuing automatically.
Three replacements: voluntary continuation (apply within 20 days), National Health Insurance / kokuho (notify in about 14 days), or joining a family member's plan as a dependent (no fixed deadline).
If you lost the job involuntarily, kokuho can count last year's salary income at just 30% when setting your premium.
Which option is cheapest depends on your household and income, so get a real estimate from both sides before choosing.

The clock that matters here does not start on your last day at the office; it starts the day after, and it is measured in days. The moment your employment formally ends, so does your coverage under the employer's health insurance (kenkō hoken 健康保険): no grace period, nothing renewing on its own. Almost everyone then chooses among the same three replacements: voluntary continuation, National Health Insurance, and joining a family member's plan as a dependent. Two of the three carry hard deadlines counted in days, not weeks. Which one is cheapest genuinely depends on your household, your income, and how long you expect to be between jobs, and no guide can settle that from outside. What this one can do is make sure you see the menu and the deadlines before you choose.

The day your coverage actually ends

Your coverage under your company's plan runs through your official retirement date (taishoku-bi 退職日) — the date recorded in your company's paperwork, not necessarily the last day you physically sat at your desk (paid leave taken at the end of employment is still employment). You are generally expected to return your health insurance card (kenkō hoken shō 健康保険証) to your employer on or shortly after that date, and using it after coverage ends is not permitted. The date that actually matters for the deadlines below is the day after your retirement date — the point at which you formally lose insured status. Every clock in this guide starts counting from there, not from your last physical day at work.

Three paths, one decision

Once your employer's coverage ends, you generally have three options. None of them happens automatically — each one requires you to apply, and two of the three have hard deadlines measured in days, not weeks.

Once your employer's coverage ends, three paths are open. Two are on a hard clock counted from the day after your retirement date; joining a family member's plan has no single fixed deadline. Details and conditions for each are in the sections below.

1. Voluntary continuation (nin'i keizoku 任意継続被保険者制度)

This lets you keep your former employer's health insurance for up to two years after leaving, as an individual policyholder rather than an employee. Two conditions apply: you need at least two continuous months of insured status immediately before leaving (this can be built up across different employers or insurers, as long as there is no gap in coverage), and you must apply within 20 days of the day you lose insured status — if day 20 falls on a weekend or public holiday, the deadline moves to the next business day, but it does not extend for any other reason. (Source: Japan Health Insurance Association / Kyōkai Kenpo, confirmed 2026-07-15.)

The trade-off is cost: your former employer stops subsidizing half the premium, so you now pay the full amount yourself. The premium is calculated from your "standard monthly remuneration" (hyōjun hōshū getsugaku 標準報酬月額) at the time you left — but that figure is capped at an upper limit set annually across all Kyōkai Kenpo members (¥320,000 for fiscal year 2026), so the premium does not keep scaling upward without limit for higher earners. (Source: Kyōkai Kenpo, FY2026 announcement, confirmed 2026-07-15.) Existing dependents can generally be added to a voluntary continuation policy at no separate premium, provided they meet the income criteria described in the dependent option below. Coverage can also end earlier than two years in specific situations — for example, once you start a new job with its own employer-based insurance — so treat two years as a maximum, not a guarantee.

2. National Health Insurance (kokuho 国民健康保険)

Kokuho is administered locally, by the city, ward, or town office where you live, rather than by a national association. Most municipalities ask you to notify their National Health Insurance section within about 14 days of losing your employer's coverage, bringing proof of when that coverage ended and identification; the exact window and required documents are set by your municipality, so confirm with your local office. (Source: City of Yokohama, National Health Insurance English guidance, confirmed 2026-07-15.)

Premiums are calculated from your prior calendar year's income rather than your current situation, and the exact calculation and rate differ by municipality. Kokuho also has no concept of a "dependent" — everyone in a kokuho household, including a non-working spouse or children, is assessed individually. One structural relief worth knowing about: if you lost your job involuntarily — dismissal, company insolvency, or certain non-renewed contracts, reflected in the discharge reason on your Employment Insurance Recipient Certificate (koyō hoken jukyū shikaku sha shō 雇用保険受給資格者証) — a nationwide statutory relief measure has your prior year's salary income counted at just 30% of its actual value when your kokuho premium is calculated, from the day after you left through the end of the following fiscal year. The measure is set nationally and applied through each municipality's premium calculation; ask your ward or city office whether you qualify, and bring your certificate. (Sources: Ministry of Health, Labour and Welfare, and City of Shibuya, National Health Insurance premium relief for involuntarily unemployed persons, confirmed 2026-07-15.)

3. Joining a family member's plan as a dependent (fuyō 被扶養者)

If you have a spouse or qualifying family member with employer-based health insurance, you may be able to join their plan at no separate premium. The general income threshold is an expected annual income under ¥1.3 million (a higher threshold of ¥1.5 million currently applies to dependents aged 19 to 22 — that is, 19 or over but under 23 — excluding spouses), and you generally need to be primarily supported by that family member's income; the criteria are set nationally but applied by each insurer, and thresholds are revised periodically. (Source: Ministry of Health, Labour and Welfare, confirmed 2026-07-15.)

One point worth stressing, because it matters most to exactly the person reading this guide: unlike kokuho, which looks backward at your prior year's income, dependent eligibility is judged on your expected income going forward — broadly, what you anticipate earning over the year ahead, counted from the point you would join the plan. Earning well above ¥1.3 million last year does not by itself disqualify you: if your expected income after leaving your job is below the threshold, you may still qualify from the day after your employment ends. How that expected income is assessed — including what counts toward it — is determined by the family member's insurer, so do not rule yourself out based on last year's payslips; have the family member ask their insurer directly. (Source: Ministry of Health, Labour and Welfare, confirmed 2026-07-15.)

This option only exists if such a family member and plan are available to you — and it is not available at all if the family member's own coverage is kokuho, since kokuho does not have a dependent category.

There is no universally "better" option

Which of these ends up cheaper or more practical depends on your household composition, your income last year versus this year, whether you have dependents of your own, and how long you expect the gap to last. The practical move, and one both systems generally support, is to request an actual premium estimate from both sides before you decide: your former employer's insurer (or your local Kyōkai Kenpo branch) for voluntary continuation, and your municipal National Health Insurance section for kokuho. Comparing two real numbers for your own situation is more reliable than any general rule of thumb, including anything in this guide.

A short timeline to work from

Your retirement date — coverage under your employer's plan is active through this date. Return your health insurance card to your employer around this time.
The day after — you lose insured status. This is day one for both deadlines below.
Within ~14 days — if choosing kokuho, notify your municipal National Health Insurance section (confirm the exact window locally).
Within 20 days — if choosing voluntary continuation, submit your application to your former employer's insurer or Kyōkai Kenpo branch. This deadline is firm.
As soon as practical — if joining a family member's plan, apply through that family member's insurer; there is no single deadline that applies everywhere, but the sooner you apply, the shorter any coverage gap.

If you end up with a coverage gap

If you need medical care after your employer's coverage ends and before your next enrollment takes effect, you will generally be asked to pay the full cost yourself at the time of treatment. Whether and how that can be reconciled afterward — through backdated enrollment or reimbursement — depends on which option you end up choosing and the specific rules of the insurer or municipality involved. Do not assume automatic backdating; ask the office you are enrolling with directly, and try to close the gap as quickly as the deadlines above allow rather than relying on it working out after the fact.

The bills and refunds that outlast the job

Health insurance is rarely the only thing that shifts when you leave a Japanese employer. If money coming in while you search for the next job matters as much as money going out for coverage, our guide to unemployment insurance and Hello Work covers the separate koyo hoken system — including the visa-specific catch if your period of stay runs out before your job search does. The bill that ambushes the most people is residence tax (juuminzei), billed roughly a year in arrears — so it can arrive months after your last paycheck, worked out on what you were earning before you left. If you are leaving Japan for good rather than moving between jobs, there is money pointing the other way too: the pension lump-sum withdrawal can return part of what came out of your paychecks, but only if you claim it yourself. And if you ever want to see where the "standard monthly remuneration" behind your premiums actually comes from, it is broken out line by line in a Japanese payslip. If a keiyaku shain contract ending, rather than a resignation, is what triggered this whole process, our guide to Japanese employment contract terms covers how fixed-term contracts and the five-year conversion rule generally work. And if explaining any of this at an insurer's counter in Japanese is part of what feels hardest about the whole process, our guide to learning Japanese while working full-time compares ways to build that vocabulary around a job's schedule rather than a classroom's. And once you know which coverage applies to you, our guide to finding English-language medical help in Japan covers who to call the first time you actually need to use it — and the same coverage pays for basic dental treatment too, which our guide to dental care in Japan breaks down separately. Most of these arrive by post rather than email, often as a sealed postcard or a signed-for envelope specifically because they carry your financial details; our guide to telling important mail from junk in Japan covers how to recognize that kind of envelope on sight, before you've even opened it.

This guide is general information about how the system works, not an assessment of your specific situation, and not a substitute for an estimate from Kyōkai Kenpo, your municipal office, or a licensed labor and social security attorney (shakai hoken rōmushi 社会保険労務士) for anything procedural or case-specific. See the disclaimer for more.

This guide picks up specifically where the resignation process itself leaves off. If you are still working through notice periods, your last working day, or what to hand in and collect before you go, that ground is covered in more depth in our companion book, How to Quit Your Job in Japan.

Sources

All sources below were checked on 2026-07-15.