Technical article

Social Security in Japan and South Korea: The Only Two Agreements in Asia

The SSA overview page lists the two Asian countries with a US agreement, and the dates they came into force.

By Neil Solomon · 4 min read

Picture a couple named Walter and Janet. Both are 66, from Oregon. Walter worked 35 years in the US. Janet worked for a few years in Tokyo as a young woman. They like the idea of retiring in Japan or Korea. They ask two things. Will our Social Security still reach us? And does time worked in one country ever help in the other?

I read the Social Security Administration (SSA) and Treasury pages on 10 October 2026.

The agreements

The SSA overview page lists the two Asian countries with a US agreement, and the dates they came into force.

The page says these agreements "eliminate dual Social Security taxation" and "help fill gaps in benefit protection for workers who have divided their careers." The page names only these two as Asian. (Page metadata shows certified 25 November 2019; the table has since been updated, as it lists an entry dated 1 September 2026 for another country.)

Combining your years

Both country pamphlets use the same first test. To have foreign credits counted toward a US benefit, "you must have earned at least six credits" in the US. The pamphlets say that is generally about one and one-half years of work. If you already qualify on US credits alone, the US does not count the foreign ones.

For the other country's benefit, the minimums differ:

• Japan: "you must have at least one month of coverage credited under the Japanese system."
• South Korea: "you must have at least 18 months of coverage credited under the Korean system."

The SSA overview adds that a worker reaching 62 in 1991 or later "generally needs 40 calendar quarters of coverage to be insured for retirement benefits," which is why the agreements matter to those who fall short of that.

Working there, or running a business

Paraphrase from the pamphlets. Japan: a self-employed person who moves a business for five years or fewer generally stays under the first country's system, and an employee sent to Japan needs a certificate of coverage (form J/USA 6) requested by the Japanese employer. South Korea: the agreement covers workers age 18 to 59 under Korea's National Pension Act, and does not cover civil servants, military personnel or private school teachers. Self-employed people living in Korea are assigned Korean coverage.

Getting paid

The Japan pamphlet says: "Japanese benefits are paid by direct deposit on the 15th of even-numbered months in Japan." To apply from Japan, it directs you to the Federal Benefits Unit at the US Embassy in Tokyo or to a Japanese social security office. For South Korea, the pamphlet gives the Federal Benefits Unit at the US Embassy in Manila, Philippines, as the contact. I would check that with SSA before relying on it.

What about tax?

This part is only partly confirmed.

• South Korea: the Treasury explanation of the tax treaty, as the page summary returned it, puts US Social Security payments to a Korean resident in Article 24, which says they "will be taxable only in the first-mentioned Contracting State." Read for US benefits, that points to the United States. The same summary says the treaty's saving clause (the part that lets the US tax its own citizens) does not override that article. I treat this as a paraphrase.
• Japan: the Treasury explanation I could reach was cut off before the Social Security article. What I can say is that its saving clause says the US may tax its citizens "as provided in their internal laws." Which country taxes a US Social Security benefit paid to someone living in Japan is not stated on an official page in the sources.

What is left open

• The Japan treaty rule on Social Security and pensions (Article 17).
• Any pension lump-sum refund rules in Japan: not checked.
• Dates on the two pamphlets beyond the SSA page metadata.
• How local taxes in either country treat your benefit.