Health Insurance in Japan 2026: Understanding Kenpo and Kokuho

When working in Japan, you will see health insurance premiums deducted directly from your pay slip every month. Whether you work for a company, do part-time jobs, or are currently unemployed waiting for a new job, you will fall under one of two different health insurance systems. Knowing which system you belong to and the amounts deducted will help you budget your expenses more easily and ensure you do not lose your benefits when you get sick. 😊

Two parallel systems: 健康保険 and 国民健康保険

Health insurance in Japan is divided into two parallel branches. The first branch is company health insurance (健康保険, kenkō hoken), which people often abbreviate as 健保 (kenpo) or Shakai Hoken. This category is for full-time employees, technical interns, and eligible part-time workers. The most common managing organization is the Japan Health Insurance Association (協会けんぽ, Kyokaikenpo), or specific insurance organizations for each industry (組合, kumiai).

The second branch is the national health insurance (国民健康保険, kokumin kenkō hoken), often called 国保 (kokuho) for short. Anyone who does not fall under company insurance enters 国保, including language school students, university students, freelancers, or those who have quit their jobs and are waiting for a new one. The Immigration Services Agency (ISA) states in the Guidebook on Living and Working that foreigners staying in Japan for more than 3 months without company insurance must enroll in the national health insurance.

協会けんぽ 2026: Rates by prefecture and child support contributions

If you work for a company and pay insurance through 協会けんぽ, the monthly premium is calculated by multiplying your standard remuneration with the rate of the prefecture where the company is headquartered. This amount is split equally between you and the company (check the specific rates at 協会けんぽ), and is deducted directly from your monthly salary. One great benefit is that when you bring your spouse or children over as dependents (with no or low income), your family members get covered under your insurance without you having to pay any extra money.

From fiscal year 2026 (calculated from the March 2026 salary, actually paid in April), the difference in health insurance rates among prefectures is clearly visible. Tokyo’s rate is 9.85%, the lowest in the country is Okinawa prefecture at 9.44%, and the highest is Saga prefecture at 10.55%.

Besides the main health insurance, you should note two smaller deductions. Anyone from 40 to 64 years old will have an additional deduction for long-term care insurance (介護保険, kaigo hoken) with a uniform nationwide rate of 1.62%. The second deduction, collected from April 2026, is the child support and child-rearing contribution (子ども・子育て支援金, kodomo kosodate shienkin). This applies a 0.23% rate nationwide to contribute to a fund supporting families raising young children.

国保: Calculation by household and conversion procedures

While company insurance is calculated individually, the national health insurance (国保) is calculated per household. This means if you bring your spouse over, the administration will calculate the total premium for the whole family. The household premium consists of two parts: an income-based portion from the previous year for each individual (based on ability to pay), plus an equal per capita portion (based on benefits). Under 国保, there are no free dependents; the fixed per capita amount is added for every person in the house.

Each ward or city office (役所) determines its own calculation method, payment deadlines, and collection methods. The maximum premium ceiling a household has to pay is also set locally (remember to check directly at your local 役所). As a result, two people with the same income living in different wards might pay different 国保 premiums. Payment slips (払い込み slips) are sent to your mailbox monthly or quarterly, and you can just take them to a convenience store to pay.

Switching insurance when quitting a job is where people get most confused. After quitting your old company and returning the company insurance card, you must bring your residence card (在留カード) to the 役所 to enroll in 国保 (the specific deadline depends on the locality, so check at your 役所). Do not delay this, because they will still retroactively collect the full amount starting from the day you quit. When you find a new job and get a new company insurance card, you must also take that card to the 役所 to cancel your 国保. If you forget this step, the 国保 payment slips will keep coming regularly, resulting in you being billed twice.

Part-time insurance: Major changes from October 2026

For those working part-time (baito) or on short-term contracts, the conditions for companies to cover health insurance and pensions are now much more relaxed. Previously, the biggest barrier for part-time workers to join company insurance was that their monthly salary had to be ¥88,000 or more. Many part-timers had to watch their hours closely for fear of exceeding this limit and having to pay their own insurance.

Starting from October 2026, the Ministry of Health, Labour and Welfare (MHLW) has completely removed this ¥88,000/month threshold. Many part-time workers only need to meet the remaining conditions to have their social insurance covered by the company. At this point, the company covers half of the cost instead of you having to pay 100% out of your own pocket for 国保 like before, and medical and future pension benefits are also much more secure.

When visiting a doctor: My Number card and medical cost ceiling

When going to the hospital, the reception procedures have also changed. The previous paper health insurance cards are no longer newly issued and have expired. For medical visits now, you must use a My Number card integrated with health insurance (マイナ保険証, Myna Hoken-sho). When you arrive, simply place your My Number card into the facial recognition scanner at the counter. For those who haven’t made a My Number card or haven’t registered for integration yet, the insurance agency will issue a certificate of eligibility (資格確認書, shikaku kakunin-sho). This certificate is issued free of charge, with no application required.

Usually, with insurance, you only have to pay 30% of the medical costs. If you unfortunately suffer from a severe illness, require surgery, or have a costly long-term hospital stay, Japan has a high-cost medical care benefit system (高額療養費, kōgaku ryōyōhi). From August 2026, this system applied a new ceiling. For instance, for someone under 70 years old with an annual income between ¥3,700,000 and ¥5,100,000, if the actual medical bill is ¥1,000,000, the maximum out-of-pocket amount is only about ¥93,000. The new system also aggregates the ceiling annually (from August this year to July next year) to prevent financial exhaustion for long-term patients. Using the マイナ保険証 card is convenient because the machine automatically applies this ceiling, saving you the trouble of applying for an eligibility certificate for ceiling-amount application for the hospital like before.

Official guidebooks from the administrative agency

If you want to fully understand your rights and obligations while living in Japan, you should read the Guidebook on Living and Working by the Immigration Services Agency (ISA). It provides clear details on healthcare, labor, pensions, and taxes in multiple languages. Reading this document carefully will help you avoid violations due to ignorance of the law. If any paperwork is unclear, the safest bet is to ask the local official in charge directly.

Things to do

• Review your April and May 2026 pay slips to see the new 協会けんぽ deduction (starting in April) and the child support contribution (starting in May).
• If you quit your job or change companies, remember to visit the 役所 to enroll in or cancel your 国保 (specific deadlines depend on your locality, check at your 役所).
• Part-time workers should pay attention to their contracts starting in October 2026, when the ¥88,000 condition is eliminated.
• Always carry your My Number card or 資格確認書 certificate when going to hospitals or clinics to be charged the 30% out-of-pocket rate.

That’s the basic overview! I hope this helps you better understand health insurance deductions so you can work with peace of mind! 💡

References

• 令和8年度保険料率, Japan Health Insurance Association (全国健康保険協会 協会けんぽ)
• 国民健康保険の保険料・保険税について, Ministry of Health, Labour and Welfare (厚生労働省)
• 国民健康保険制度の概要（令和5年度末時点）, Ministry of Health, Labour and Welfare (厚生労働省)
• 厚生労働省関係の主な制度変更（令和８年10月）, Ministry of Health, Labour and Welfare (厚生労働省)
• マイナンバーカードの健康保険証利用について（マイナ保険証）, Ministry of Health, Labour and Welfare (厚生労働省)
• 高額療養費制度を利用される皆さまへ, Ministry of Health, Labour and Welfare (厚生労働省)
• Guidebook on Living and Working (生活・就労ガイドブック ベトナム語版), Immigration Services Agency (出入国在留管理庁)

Last updated: September 30, 2026. Regulations and fees are subject to change, so please check the official sources above before proceeding with any procedures.