National Health Insurance
You can join National Health Insurance (NHI) at your local city or ward office. NHI is for residents (and their families) who aren’t covered by their employer’s insurance. This includes the self-employed and students. When you register your address at the ward office you’ll be guided to enrol in NHI. You will need your passport and the residence (zairyu) card you receive at the airport. No fee is charged when you join. The insurance card and bills for scheme membership (known as premiums) will be sent to your home later. City or ward offices are typically open 9:00-17:00 Monday through Friday. No appointment is needed.
Social Health Insurance (Company Insurance)
Your company will enroll you with the company insurer. It usually takes 2 weeks to a month for you to receive an insurance card. If you need treatment before your card arrives, ask the person in charge of the scheme in your company. They can normally give you a letter that acts as a temporary certificate. If not, you should be able to be reimbursed later from the insurer by presenting your receipts. Japanese hospitals normally do not reissue receipts so please keep them safe. They are also needed for your yearly tax return if you have spent over 100,000 yen for medical care.
If you are not sure which kind of insurance to join, ask your employer. Some companies still have employees join the NHI scheme.