U.S. taxes in Japan: 55% combined rate — FTC is the only viable strategy

Japan's tax system — 45% national income tax plus 10% resident tax

Japan's income tax structure has two main components that combine to produce what is arguably the highest effective income tax burden for high earners among major developed economies. Understanding the difference between the two — and when each is assessed — is essential for U.S. expats managing their FTC calculations.

National income tax (shotoku-zei)

Japan's national income tax is levied on annual income at progressive rates, with the following 2025 brackets (approximate, converted from yen thresholds):

A 2.1% surtax on national income tax is also levied (the "Special Reconstruction Income Tax"), bringing the effective national top rate to approximately 45.945%.

Resident (inhabitant) tax (jumin-zei)

Resident tax is a prefectural and municipal tax on income, assessed the year following the income year at a flat combined rate of approximately 10% (4% prefectural + 6% municipal in most areas). This creates an important timing consideration: your resident tax for 2025 income is assessed and billed in 2026. Japanese employers typically withhold resident tax starting around June of the following year.

For U.S. FTC purposes, resident tax is generally creditable as a foreign income tax — it is a tax on income levied by a foreign government subdivision. The timing difference (2025 income, 2026 assessment) creates a question about which U.S. tax year the credit applies to. Most practitioners take the position that resident tax is creditable in the year it is actually paid or accrued under Japanese law.

The US-Japan tax treaty — a modern and protective agreement

The current US-Japan income tax convention was signed in 2003 (replacing the 1971 treaty) with an updated protocol in 2013. It is one of the more modern treaties in the U.S. network and contains detailed provisions relevant to American expats in Japan.

Key articles for 🇺🇸 Americans in Japan

Article 17 — Pensions: Japanese pension income paid to U.S. residents is generally taxable only in the U.S. under the treaty, with Japan exempting payments from Japanese withholding. Contributions to qualifying Japanese pension schemes may receive treaty-based deferral treatment for U.S. tax purposes. This is particularly important for 🇺🇸 Americans participating in Kosei Nenkin (Employees' Pension Insurance).

Article 10 — Dividends: Japanese withholding on dividends is reduced to 10% for U.S. portfolio investors under the treaty (from Japan's standard 20.315% on investment income). For direct investors with 10%+ shareholding in a Japanese company, the rate is reduced to 5%. These withheld amounts generate FTC for U.S. filers.

Article 11 — Interest: Interest paid from Japan to U.S. residents is generally exempt from Japanese withholding under the treaty. Japanese bank account interest, therefore, is taxable in the U.S. but not subject to Japanese withholding.

Article 23 — Relief from double taxation: The treaty's double-taxation relief article establishes the FTC framework under which Japan credits U.S. taxes on Japanese-source income, and the U.S. credits Japanese taxes on U.S.-source income for Japanese residents. For U.S. citizens, this article works alongside the FTC rules of the Internal Revenue Code.

The savings clause (Article 1(4)): As with all U.S. tax treaties, the savings clause preserves the U.S. right to tax its citizens on worldwide income as if the treaty did not exist. U.S. citizens in Japan cannot use the treaty to eliminate U.S. filing obligations or U.S. taxation rights — the treaty primarily facilitates FTC mechanics and reduces Japanese withholding on certain passive income.

Why FEIE almost never works in Japan

The Foreign Earned Income Exclusion is an option available to 🇺🇸 Americans who qualify as foreign residents or who meet the physical presence test — and 🇺🇸 Americans in Japan can technically qualify. But for virtually all American workers in Japan, the FEIE is either useless or actively harmful compared to the FTC. Here is why:

The stacking rule — FEIE's hidden cost at high income levels

When you use FEIE, the income above the exclusion limit is taxed at the rate that would have applied had you earned the excluded amount first. This means your first dollar of income above $130,000 (the 2025 FEIE limit) is taxed at the marginal rate applicable to $130,000 + whatever you earned above that — not at the rate applicable to your total income minus the exclusion. At Japanese income levels, this stacking effect typically produces higher effective U.S. rates on the supra-exclusion income than would result from simply using FTC.

Lost FTC when FEIE is used

When you elect FEIE, you cannot also take the FTC on the excluded income. The Japanese income tax you paid on the excluded wages is permanently forfeited as a credit — it does not carry forward. In Japan, where Japanese taxes on those wages almost certainly exceed U.S. rates, this wasted FTC represents real money. By contrast, excess FTC on non-excluded income carries forward 10 years and back one year.

When might FEIE make sense in Japan?

FEIE might be appropriate for an American earning a very low income in Japan — perhaps a part-time worker or new arrival earning below the exclusion limit entirely, where the FTC would produce no benefit regardless. But this is a narrow exception. For any American earning income that would be taxable in the U.S. after deductions and FTC calculations, the FTC is almost always the superior strategy in Japan.

Japanese pensions — Kokumin Nenkin and Kosei Nenkin

Japan has a two-tier mandatory public pension system. Understanding how each tier works — and its U.S. tax treatment — is essential for American employees in Japan.

Kokumin Nenkin (National Pension)

The Kokumin Nenkin is Japan's basic first-tier pension, covering all Japanese residents aged 20–60 including foreign nationals. Contributions in 2025 are a flat monthly amount (approximately ¥16,980 per month). Self-employed individuals and those not covered by an employer pension plan pay directly. Employees are typically enrolled through the Kosei Nenkin system instead (which includes Kokumin Nenkin as a base).

Kosei Nenkin (Employees' Pension Insurance)

The Kosei Nenkin (EPI) is the second-tier earnings-related pension for employees. Contribution rates in 2025 total approximately 18.3% of standard monthly remuneration (split equally between employer and employee — about 9.15% each). There is a contribution ceiling of approximately ¥650,000 per month.

U.S. treatment of Japanese pension contributions

Under Article 17 of the US-Japan treaty, contributions to Kosei Nenkin by an American employee working in Japan may be treated as tax-deductible for U.S. income tax purposes — similar to how U.S. 401(k) contributions reduce taxable income. This treaty-based deduction requires disclosure on Form 8833. The investment growth inside the pension system accumulates on a tax-deferred basis for U.S. purposes under the treaty.

The US-Japan totalization agreement ensures 🇺🇸 Americans working in Japan under a Japanese employer generally contribute to the Japanese pension system only — not to U.S. Social Security and Kosei Nenkin simultaneously. Your employer coordinates this with a Certificate of Coverage from SSA.

FBAR and Japanese pension accounts

Japanese government pension funds (Kokumin Nenkin, Kosei Nenkin) are administered by the Japan Pension Service — a government agency. The FBAR reporting question for government pension schemes is similar to Korea's NPS: whether the participant has a distinct financial account with a determinable balance at a "financial institution." Many practitioners take the position that mandatory government pension programs with individual account balances are reportable, particularly as the Japan Pension Service does provide individual account records. Conservative practice is to include pension account balances in FBAR calculations.

iDeCo — Japan's individual defined contribution pension

iDeCo (Individual-type Defined Contribution pension plan) is Japan's private defined-contribution pension scheme, similar in concept to a U.S. IRA. Contributions are voluntary, up to annual limits that vary based on whether you are also covered by a workplace plan. iDeCo contributions are deductible against Japanese income tax, and investment growth is tax-deferred under Japanese law. iDeCo has grown significantly in popularity since reforms in 2017 expanded eligibility.

Why iDeCo is complicated for U.S. filers

iDeCo is a private defined-contribution pension account held at a financial institution, not a government pension scheme. This means it has clearer FBAR-reportable status than the national pension programs. More importantly, the U.S. tax treatment of iDeCo is uncertain:

• The IRS has not issued specific guidance on iDeCo's status under U.S. tax law.
• If iDeCo does not qualify as a "pension fund" under the US-Japan treaty's Article 17 provisions, contributions are made from after-tax (U.S.) income and inside build-up may be currently taxable in the U.S.
• The investments held inside iDeCo — often Japanese mutual funds — may be PFICs, creating additional U.S. tax complications on top of the uncertain pension treatment.

Japanese inheritance tax — a critical planning issue for long-term residents

Japan's inheritance tax (sozoku-zei) is uniquely aggressive compared to most developed countries and has undergone significant changes that directly affect foreign residents — including 🇺🇸 Americans on long-term visas.

The 10-year rule for foreign residents

Prior to 2017, Japan's inheritance tax generally applied only to Japanese-situs assets (assets located in Japan) for foreign residents who did not intend to live in Japan permanently. However, reforms in 2017 and subsequent changes have created a new framework:

• Foreign residents (including 🇺🇸 Americans) who have been resident in Japan for a cumulative total of more than 10 of the preceding 15 years are treated as "unlimited taxpayers" — subject to Japanese inheritance tax on their worldwide assets.
• Foreign residents who have been in Japan for 10 or fewer of the past 15 years are "limited taxpayers" — subject to Japanese inheritance tax only on Japanese-situs assets.

This 10-year threshold means 🇺🇸 Americans on long-term work visas (Engineer/Specialist in Humanities visas, highly skilled professional visas) who have been in Japan for 10+ cumulative years are potentially subject to Japanese inheritance tax on their worldwide estate — including U.S. retirement accounts, U.S. real estate, and other non-Japanese assets.

Japan's inheritance tax rates

Japanese inheritance tax rates are steep, with marginal rates reaching 55% on the largest inheritances. The basic exemption is ¥30 million plus ¥6 million per heir, but for large estates this exemption is quickly exceeded. The combination of potential U.S. estate tax (though the U.S. estate tax exemption is currently $13.6 million per person in 2024) and Japanese inheritance tax creates double estate tax exposure for long-term American residents in Japan.

Capital gains in Japan — 20.315% flat rate

Japan taxes capital gains from securities (stocks, bonds, investment trusts) at a flat rate of 20.315% — which breaks down as 15.315% national income tax (including the reconstruction surcharge) plus 5% resident tax. This flat rate applies regardless of holding period — there is no Japanese distinction between short-term and long-term gains like the U.S. system.

FTC implications for capital gains

For U.S. FTC purposes, Japanese capital gains tax on securities goes into the passive income FTC basket. U.S. long-term capital gains are taxed at 0%, 15%, or 20% depending on income level. For 🇺🇸 Americans in the 15% or 20% U.S. long-term rate category, the 20.315% Japanese rate may generate excess FTC in the passive basket — meaning more Japanese tax was paid on those gains than U.S. tax owed, creating credits that can only offset U.S. tax on other passive income.

Japanese brokerage accounts and NISA

Japan's NISA (Nippon Individual Savings Account) is a tax-advantaged investment account where capital gains and dividends are exempt from Japanese tax. The expanded "New NISA" introduced in 2024 allows significantly higher annual contributions. For U.S. filers, NISA accounts are FBAR-reportable, and the Japanese tax exemption is not recognized for U.S. purposes — income and gains in NISA accounts are fully taxable for U.S. filers in the year realized. Additionally, investments held inside NISA accounts that are Japanese investment trusts (toshin) are almost certainly PFICs under U.S. tax rules, creating additional compliance complexity.

FBAR for Japanese bank accounts

🇺🇸 Americans living in Japan with combined foreign accounts exceeding $10,000 at any point during the year must file the FBAR. This encompasses virtually every American working in Japan. Japanese financial institutions whose accounts are FBAR-reportable include:

• Mizuho Bank — one of Japan's three megabanks, widely used for expat banking
• MUFG (Mitsubishi UFJ Financial Group) — Japan's largest bank by assets
• SMBC (Sumitomo Mitsui Banking Corporation) — the third of Japan's three megabanks
• Japan Post Bank (Yucho Bank) — Japan's largest bank by deposits, accessible at post offices nationwide
• Rakuten Bank — Japan's largest internet bank, popular with tech-savvy expats
• Sony Bank — internet bank with favorable foreign currency exchange rates, popular with expats
• SBI Sumishin Net Bank — digital bank with strong English interface
• Shinsei Bank — frequently used by expats for international transfers and multi-currency accounts

Japanese brokerage accounts (at SBI Securities, Rakuten Securities, Nomura Securities, and others) are also reportable. iDeCo accounts held at private financial institutions are likely reportable. NISA accounts are reportable.

Self-employment (Kojin Jigyo) in Japan

🇺🇸 Americans who operate as self-employed individuals in Japan — as consultants, freelancers, English teachers running private lessons, artists, or business owners — register as Kojin Jigyo (sole proprietors). They file a Japanese individual income tax return (kakuteishinkoku) that includes a business income schedule.

U.S. self-employment tax considerations

Self-employment income from Japan is reported on U.S. Schedule C. The U.S.-Japan totalization agreement generally covers self-employed 🇺🇸 Americans who are covered by Japanese social insurance (including National Pension and National Health Insurance as a sole proprietor), eliminating the requirement to also pay U.S. self-employment tax. However, properly documenting coverage under the Japanese social system and obtaining the totalization agreement Certificate of Coverage is essential — without documentation, the IRS may assess U.S. SE tax.

Japanese consumption tax (JCT)

Japanese sole proprietors with taxable sales exceeding ¥10 million in two years prior are required to register for and collect Japanese consumption tax (Shohi-zei) — Japan's VAT, currently 10%. Consumption tax is a transactional tax rather than an income tax and is not relevant to the FTC calculation, but it creates additional compliance obligations for American business owners in Japan.

Practical filing steps for 🇺🇸 Americans in Japan

1. File your Japanese kakuteishinkoku (income tax return) if required — Japanese employees with only wage income generally do not need to file separately (year-end adjustment handled by employer), but those with side income, significant interest/dividend income, or business income must file. Japanese returns are due March 15.
2. Gather Japanese tax documentation. Your Japanese employer provides a gensen choshu hyo (withholding tax certificate) — similar to a W-2 — each January for the prior year. This is your primary documentation for FTC calculations.
3. Determine resident tax owed for FTC purposes. Resident tax is assessed by your municipality in June based on prior year income. The amount on your resident tax notice (jumin-zei nozei tsuchisho) becomes creditable in the year paid.
4. Prepare Form 1116 for FTC. Categorize income into baskets: general (wages), passive (investment income, capital gains). Calculate the FTC limitation separately for each basket.
5. Identify all Japanese financial accounts. List every bank account, brokerage account, iDeCo account, NISA account, and pension account with institution, account number, and maximum balance.
6. File FBAR by April 15 (automatic extension to October 15) via FinCEN's BSA e-filing system.
7. File Form 1040 with Form 1116. June 15 standard expat deadline; extend to October 15 or December 15 as needed.
8. File Form 8938 (FATCA) if total foreign financial assets exceed $200,000/$300,000 (single abroad) or $400,000/$600,000 (MFJ abroad).
9. Address treaty-based positions on Form 8833 for pension contribution deductibility or other treaty benefits claimed.