Does the U.S.-Japan tax treaty protect my Japanese pension income from double taxation?

Yes. Under the U.S.-Japan tax treaty, employer and employee contributions to your Japanese pension (Kokumin Nenkin, Kosei Nenkin, or corporate DC/DB plan) are deferred from current U.S. tax, and plan earnings are generally not taxed until distribution. However, you must file Form 3520-A annually to claim the treaty deferral, and failure to file carries severe penalties.

Japanese pension treaty relief mechanics:

• Contributions: Deferred from U.S. taxation in the year made (both employer and employee portions)
• Earnings: Not taxed annually; deferred until distribution
• Form 3520-A: Must be filed annually (due March 15, extendable to September 15) to establish the treaty-protected status; failure to file results in a penalty of the greater of $10,000 or 5% of account value
• FBAR: Required if your Japanese pension plus all foreign accounts exceed $10,000 at any point in the year
• Form 8938: Required if foreign financial assets exceed $200,000 (single) or $400,000 (MFJ) at year-end

Treaty eligibility for Japanese pensions:

• Treaty deferral applies only to “personal pension arrangements” under Article 18 of the U.S.-Japan tax treaty
• Corporate DB/DC plans and public Kosei Nenkin typically qualify
• Kokumin Nenkin (National Pension) does not qualify (it is not an employer plan)

Filing timeline and penalties:

If you miss a single year of Form 3520-A filing, you lose treaty protection for that year, and the entire account balance becomes taxable, plus a $10,000+ penalty. For broader Japan expat tax compliance, see Americans in Japan: U.S. Tax Rules and Filing.