If you're living in Japan — whether you're a company employee, freelancer, student, or long-term resident — joining a public health insurance system is not optional. Japan requires all residents to be enrolled in one of two main health insurance programs:

1. Shakai Hoken (Social Insurance)
2. Kokumin Kenkō Hoken (National Health Insurance)

While both systems offer access to quality medical care, there are important differences in how they work, who qualifies, and how much they cost. This guide explains the essentials, especially for people working in Japan or managing their own insurance.

What Is Shakai Hoken?

Shakai Hoken (社会保険), or Social Insurance, is a government-backed system for employees. It provides coverage for:

1. Health insurance (including medical, dental, and maternity care)
2. Public pension (Employees’ Pension Insurance)
3. Long-term care insurance (for residents age 40+)

This insurance is mandatory for company employees who meet certain conditions. It protects not only workers, but also their dependents, by offering affordable healthcare access and retirement support.

Who Must Be Enrolled in Shakai Hoken?

Your employer is legally required to enroll you in Shakai Hoken if you meet all of the following:

1. You work 20 hours or more per week
2. You earn at least ¥88,000 per month
3. Your expected employment period is 2 months or longer
4. You are not a full-time student
5. Your company has 50 or more employees

If you qualify, enrollment is automatic and starts on your first day of work. You cannot opt out, and companies cannot avoid enrollment to cut costs.

How Much Does Shakai Hoken Cost?

Shakai Hoken premiums are based on your total salary, including bonuses. The cost is shared equally between you and your employer.

Typical breakdown:

1. Around 14% of your monthly salary goes to health insurance
2. Around 18% goes to pension
3. Total: about 32% of your salary, with half paid by you and half by your employer

For example, if you earn ¥300,000 per month, around ¥57,000 may be deducted (your half), and your employer pays the same. Rates vary slightly depending on your region and insurer, but they follow national guidelines.

What Is Kokumin Kenkō Hoken?

Kokumin Kenkō Hoken (国民健康保険), or National Health Insurance, is for people not enrolled in employee insurance. This includes:

1. Freelancers and self-employed individuals
2. Part-time workers who don’t meet Shakai Hoken conditions
3. Students
4. Unemployed residents
5. Retirees under age 75

This system covers health care only. If you’re on Kokumin Kenkō Hoken, you must enroll in the National Pension (Kokumin Nenkin) separately if you’re between ages 20 and 59.

Who Cannot Join Kokumin Kenkō Hoken?

You are not eligible to join if:

1. You are already covered by Shakai Hoken or another company/union insurance
2. You receive public welfare assistance
3. You are in Japan on a short-term visa (3 months or less)
4. You are a diplomat
5. You are age 75 or older (you join a different system for elderly residents)

How Much Does Kokumin Kenkō Hoken Cost?

Premiums are calculated by your local city or ward office based on:

1. Your previous year’s income
2. The number of people in your household
3. Any fixed assets

Because there is no employer sharing the cost, you pay 100% of the premium yourself. In general, monthly premiums can range from ¥15,000 to over ¥40,000, depending on your income and where you live. Low-income households can apply for reduction or exemption.

Why Freelancers and Part-Time Workers May Pay More

One thing many people don’t realize is that self-employed people and freelancers often pay more for health insurance than full-time company employees earning the same amount.

Why? Because:

1. Under Shakai Hoken, employers pay half the premium
2. Under Kokumin Kenkō Hoken, you pay the full amount yourself

So, two people earning the same salary could pay very different amounts for insurance — just based on employment status. A freelancer may end up paying 1.5 to 2 times more than a company employee. This is especially important to consider if you’re thinking of going freelance or reducing your hours.

Summary

Final Notes

Japan’s public health insurance system is built to offer everyone access to medical care. But the type of insurance you’re enrolled in can affect how much you pay and what’s included.

If you're working full-time or meet the part-time criteria, make sure your employer enrolls you in Shakai Hoken — it's not just a benefit, it’s a legal requirement. If you’re not employed or working independently, Kokumin Kenkō Hoken keeps you covered, but be aware that the cost may be higher.

Understanding these systems can help you avoid mistakes, plan your finances better, and make informed career choices in Japan.