Without an agreement, an employee sent to Japan by an overseas parent and paid through the Japanese entity must join Japanese pension and health insurance while still contributing at home. Social security agreements fix that. Under the usual rule, an employee seconded for an expected period of five years or less stays in the home country's system and is exempt in the host country, on the strength of a certificate of coverage. Longer assignments, or people hired locally, join the host country's system.
Most agreements also let contribution periods in both countries be added together to meet minimum qualifying periods for a pension. The agreements with the UK, South Korea, China and Italy only prevent double contributions and do not combine periods. What each agreement covers also varies: some include health insurance and employment insurance, others cover pensions only.
As of June 2026, Japan's agreements in force covered 24 countries, including the United States, Germany, the UK, France, Canada, Australia, India, China, the Philippines, Italy and, from December 2025, Austria. An agreement with Poland was signed in April 2026, and negotiations were under way with Turkey, Norway and Vietnam. Several major sources of talent in the region, including Singapore and Hong Kong, have no agreement with Japan.
What it means for a foreign employer
- Get the certificate before the assignment starts. Without it, Japanese contributions are due from day one.
- Check what the agreement covers. An exemption from Japanese pension does not always mean an exemption from Japanese health insurance.
- Five years is a planning horizon. Extending an assignment beyond the expected period may move the employee into the Japanese system.
- No agreement means double cost. For staff from countries without one, budget for both systems, and remind leavers about the lump-sum withdrawal payment.
Sources
- Ministry of Health, Labour and Welfare, status of social security agreements as at 2 June 2026.
- Japan Pension Service, guidance on social security agreements and certificates of coverage.