Before you start

Ward registration completed
Residence card
Employment details, if enrolling through an employer scheme
My Number

Step-by-step

1
Establish which scheme you are in
Full-time employees are usually enrolled in shakai hoken by their employer, which splits contributions between you and them and includes pension. Everyone else — freelancers, part-timers, students, people between jobs — must enrol in National Health Insurance at the ward office themselves. There is no third option of being uninsured.
Via employerWho: YouWeek 1–2
2
Enrol at the ward office if your employer does not
Do it in the same visit as your address registration. Premiums for National Health Insurance are income-based and calculated on last year's income, so a first year in Japan is usually cheap and the second is not.
In personWho: YouWithin 14 days
3
Understand the 30% co-payment and the monthly ceiling
You pay 30% of most treatment costs at the counter. Above a monthly threshold that scales with income, the high-cost medical expense benefit caps what you pay — which is what makes a serious illness affordable here. Apply for a limit certificate in advance if you know a major treatment is coming.
In personWho: You
4
Enrol in the pension and keep the records
Pension enrolment is compulsory alongside health insurance. Keep your pension book and every record of contributions, because they are what you will need to claim the lump-sum withdrawal if you leave Japan.
In personWho: You
5
Register your My Number card as your insurance card
Japan has moved to using the My Number card as the health insurance card. Registering it means your treatment history and prescriptions are visible to providers with your consent, and it simplifies claiming the high-cost benefit.
OnlineWho: You
6
Claim the pension lump-sum withdrawal when you leave
If you leave Japan having contributed for at least six months, you can claim a lump-sum refund of part of your pension contributions, applied for within two years of departure. It is a substantial sum for anyone who stayed a few years and it is very commonly forgotten.
OnlineWho: YouWithin 2 years of leaving Japan

Documents you’ll need

Residence card
My Number
Health insurance card or registered My Number card
Pension handbook
Jūminhyō residence certificate

Things most newcomers don’t know

The high-cost medical expense benefit is what makes the 30% co-payment survivable.

Paying 30% of everything sounds alarming until you learn that monthly out-of-pocket costs are capped at a threshold scaling with income. A major operation or a long hospital stay costs a manageable amount rather than a catastrophic one. If you know a significant treatment is coming, applying for the limit certificate in advance means the cap is applied at the counter rather than reclaimed later.

Source: Ministry of Health, Labour and Welfare

The pension lump-sum withdrawal is real money and departing residents routinely forget it.

Anyone who contributed for at least six months can claim back part of their pension contributions after leaving Japan, applied for within two years of departure. For someone who stayed three or four years this is a meaningful sum. It requires paperwork sent from abroad and a Japanese bank account or a tax representative, which is why doing the groundwork before you leave matters so much.

Source: Japan Pension Service

National Health Insurance premiums are based on last year's income, so year two is the expensive one.

Your first year in Japan is assessed on a Japanese income of zero, which makes premiums minimal and gives a misleading impression of the cost. From the second year they are calculated on your actual earnings and rise sharply — in the same way residence tax does. Budget for the step change rather than being surprised by it.

Source: Osaka City

Dental care is inside the system here, which surprises people from Europe.

Japanese national health insurance covers dental treatment at the same 30% co-payment as everything else. Coming from the UK, Spain or France — where dental access is a separate and frequently expensive problem — this is a genuine and unadvertised advantage. Cosmetic work is excluded, but ordinary dentistry is not.

Source: Ministry of Health, Labour and Welfare