U.S. taxes for Americans in Japan

Japan has a meaningful and growing American expat population — tech workers, English teachers, military, finance professionals, and an increasing number of retirees and remote workers attracted by the Digital Nomad visa. Japan's tax system has two quirks that make U.S. expat tax planning different from European countries: the Year 5 worldwide-income trigger for long-stay residents, and the timing offset of resident tax (住民税) that catches people in their second year.

This article covers the country-specific angles.

The income tax math

Japan's national income tax rates run 5% to 45%, plus reconstruction surtax (2.1% of income tax), plus inhabitant tax (住民税) of approximately 10% (4% prefectural + 6% municipal). Effective combined marginal rates:

• Top bracket: ~55% combined
• Middle-income professional in Tokyo: ~30–35%

For nearly all U.S. professionals in Japan, Japanese tax exceeds U.S. tax on the same income. The recommended setup:

• Foreign Tax Credit (FTC) on Form 1116 zeros out U.S. tax.
• FTC carryforward accumulates (10 years).
• Roth IRA stays available.

See FEIE vs. Foreign Tax Credit.

The Year 5 trigger (永住者 / 非永住者)

This is the most-missed Japan tax rule. Under Japanese tax law, foreign residents are classified into three categories:

1. Non-resident (非居住者): in Japan less than one year. Taxed only on Japan-source income.
2. Non-permanent resident (非永住者): in Japan more than 1 year but not 5 of the last 10 years. Taxed on Japan-source income plus any foreign income remitted to Japan.
3. Permanent resident (for tax) (永住者): in Japan more than 5 of the last 10 years. Taxed on worldwide income the same as a Japanese citizen.

The "Year 5 switch" hits hard. An American who lived in Tokyo for the first four years paying Japanese tax only on Japan-source salary suddenly, in year 5, owes Japanese tax on:

• Foreign rental income
• Foreign investment income (dividends, interest, capital gains)
• Foreign-source pension income
• Worldwide capital gains

The U.S. side hasn't changed — you've always owed U.S. tax on worldwide income. But suddenly Japan is taxing the same items, and now you're using FTC across multiple income types.

For Americans planning long Japan stays: plan asset structure before Year 5. Realize U.S.-source gains in the U.S.-only window. Consider whether to consolidate or restructure investments to avoid Japanese tax complications.

The Year 2 resident tax trap

Japanese resident tax (住民税) is assessed in arrears: this year's bill is based on last year's income. You receive it in mid-year and pay over four installments (June, August, October, January).

This means:

• Year 1 in Japan: you pay national income tax on year-1 income, no resident tax yet.
• Year 2 in Japan: you pay national income tax on year-2 income, plus resident tax on year-1 income.
• Year 3 in Japan: same — resident tax catches up by one year.

For a U.S. expat who arrives mid-year and earns substantial salary, Year 2 can feel like a tax shock: ~30% national + 10% resident on Year 1's full salary. Budget accordingly.

For U.S. tax purposes, resident tax paid is creditable foreign tax in Form 1116 the year it's paid (cash basis).

NISA and iDeCo — both PFIC traps

Japan's tax-advantaged accounts are not recognized by the U.S.:

• NISA (Nippon Individual Savings Account): similar to a Roth — tax-free growth in Japan. Inside, you typically hold 投資信託 (toushin shintaku, Japanese mutual funds) which are PFICs. The U.S. side taxes both growth and PFIC excess distributions on a current basis regardless of NISA wrapper.
• iDeCo (個人型確定拠出年金, individual defined contribution pension): similar to a 401(k) in Japan, with monthly contributions to a savings plan. The U.S. side may or may not get treaty deferral — practitioners disagree. Conservative practice: treat iDeCo as currently taxable for U.S. purposes.

For Americans in Japan, the practical answer is: don't use NISA, and think carefully about iDeCo. Open a U.S. brokerage that accepts foreign addresses (Schwab International, Interactive Brokers) and hold U.S.-domiciled ETFs there.

投資信託 (toushin shintaku) — Japanese mutual funds

These are PFICs. Full stop. Every Japanese mutual fund sold by a Japanese brokerage (Nomura, SMBC Nikko, Rakuten Securities, SBI) is a PFIC for U.S. tax purposes. Even ETFs listed on the Tokyo Stock Exchange that track U.S. indexes are PFICs.

The fix is the same as everywhere else: use a U.S. broker for fund investing. See foreign mutual funds.

Pension system — Japan and U.S. Social Security

Japan's pension system has two main pillars:

• National Pension (国民年金) — mandatory for all residents 20–60.
• Employees' Pension (厚生年金) — mandatory for employees, on top of National Pension.

The U.S.–Japan totalization agreement (in force since 2005) coordinates contributions:

• Working at a Japanese employer: you pay Japanese pension contributions; you owe no U.S. FICA.
• Self-employed in Japan: you pay Japanese National Pension; you owe no U.S. SE tax. Apply for a Certificate of Coverage from the Japan Pension Service.

See totalization agreements.

When you retire, the totalization agreement aggregates contribution credits across the two systems for eligibility purposes. You'll receive partial benefits from each based on actual contributions.

Capital gains in Japan

Japan taxes capital gains in distinct categories:

• Listed securities: flat 20.315% (15% national + 0.315% reconstruction + 5% inhabitant).
• Unlisted securities: ordinary income rates, up to 55% combined.
• Real estate: 20% if held >5 years; 39% if held ≤5 years.

For U.S. tax purposes, Japanese capital-gains tax is creditable in the passive basket of Form 1116. For most filers, U.S. cap-gains tax is fully offset by the Japanese tax.

Non-permanent residents (first 5 years) only owe Japanese tax on capital gains from Japanese-listed assets or those involving Japan-source income. After Year 5, all worldwide capital gains are subject to Japanese tax.

Inhabitant tax for departure year

When you leave Japan, the Year 2 timing means you still owe inhabitant tax on the year you depart's income — even after you've left. Tax authorities will pursue overseas Americans who skip this.

The fix: pay the inhabitant tax in advance before departure (一括前納), or arrange withholding from your final salary. Don't just leave and forget — Japan can flag your re-entry years later if there's unpaid tax.

FBAR and 8938 for Japan accounts

• Japanese bank accounts (Mizuho, MUFG, SMBC, Japan Post Bank, online banks): FBAR-reportable.
• Japanese brokerage accounts: FBAR-reportable, also 8621 for any 投資信託 holdings.
• NISA, iDeCo, 確定拠出年金 (corporate DC pension): FBAR-reportable.
• Wise, Revolut Japan: FBAR-reportable.

Japan-domiciled banks rarely insist on FATCA W-9 paperwork for U.S. citizens (compared to European banks, which uniformly demand it). But your reporting obligation to the U.S. is the same regardless.

State residency

The Japanese visa system (work visa, spouse-of-Japanese-national, dependent, etc.) and resident registration (住民票) provide solid evidence of foreign residence for state-residency severance. For sticky states (CA, NY, NM, VA, SC), pair this with the standard severance steps. See state residency when abroad.

Common Americans-in-Japan mistakes

• Not planning for the Year 5 worldwide-income switch. Asset restructuring becomes harder once you're under Japanese tax on worldwide gains.
• Year 2 cash-flow shock from resident tax. Budget for it; don't let it surprise you.
• NISA contributions. Useless or worse for Americans.
• 投資信託 in any wrapper. PFIC trap.
• Forgetting the totalization Certificate of Coverage for self-employment.
• Leaving Japan without settling inhabitant tax. Comes back to bite on re-entry years later.
• iDeCo without U.S. analysis. May be a current-tax problem in the U.S.

Next steps

• FEIE vs. Foreign Tax Credit
• The PFIC trap
• Foreign mutual funds
• Totalization agreements
• State residency when abroad