For US citizens and green card holders in Japan, US tax compliance involves navigating two robust tax systems. A comprehensive US-Japan income tax treaty and a social security agreement are in place, which significantly reduces the risk of double taxation. However, complexities arise from the US tax treatment of Japanese savings and retirement accounts like iDeCo and NISA, which the IRS does not recognize as tax-advantaged, often leading to Passive Foreign Investment Company (PFIC) reporting.
US filing basics every American abroad must know
US citizens and green-card holders are taxed on worldwide income wherever they live, and usually must file Form 1040 once gross income exceeds the IRS threshold ($15,750 for single filers, $31,500 for married filing jointly, and $23,625 for head of household for 2025), even when no tax is ultimately due. The tools that reduce double taxation are the Foreign Earned Income Exclusion (FEIE, up to $130,000 for 2025 under IRC §911) and the Foreign Tax Credit. Neither is automatic. The FEIE requires a tax home in a foreign country plus either the bona fide residence test or 330 full days abroad in a 12-month period, and it reaches earned income only. The Foreign Tax Credit is figured separately for each income category under IRC §904 and is capped at the US tax on the foreign income in that category, so it reduces double taxation without guaranteeing that none remains.
Two reporting rules catch most filers in Japan: the FBAR (FinCEN Form 114), required when foreign financial accounts exceed $10,000 in aggregate at any point in the year, and Form 8938 (FATCA) for specified foreign assets above the applicable threshold. Both can carry penalties even when no tax is owed. If you are behind, the Streamlined Filing Compliance Procedures are the usual path back for non-willful taxpayers. They run on two tracks: the foreign track carries no offshore penalty but requires meeting the program's non-residency test, and the domestic track carries a 5% offshore penalty but works through amended returns, so it does not fit someone who never filed at all. Tax and interest on the catch-up years are owed whichever route applies.
US tax treaty with Japan
The United States and Japan have a comprehensive income tax treaty designed to prevent double taxation and fiscal evasion. For US citizens living in Japan, its most important function is to provide resourcing rules for foreign tax credits to prevent double taxation. However, the treaty contains a "saving clause" (Article 1, Paragraph 4) which allows the US to tax its citizens on their worldwide income as if the treaty did not exist. Because of this, Americans in Japan cannot simply use the treaty to exempt their Japanese income from US tax. Instead, they must report all income and rely on the Foreign Tax Credit to offset Japanese taxes paid against their US tax liability.
Article 10 (Dividends).
This article limits the withholding tax that the source country can impose on dividends paid to a resident of the other country. It sets the general maximum rate at 10% and provides for lower rates in specific corporate ownership scenarios. For US citizens in Japan receiving US-source dividends, Japan taxes the dividends fully as the residence country, and the treaty provides resourcing rules for foreign tax credits to prevent double taxation.
Article 11 (Interest).
This article generally eliminates withholding tax on interest payments made to a resident of the other country. However, as a Japanese resident, Japan will tax your local bank interest (typically at 20.315%), and the US will also tax it due to the saving clause, requiring a foreign tax credit to prevent double taxation.
Article 12 (Royalties).
This article governs the taxation of royalties. Under the current treaty, it generally eliminates withholding tax on royalties paid to a resident of the other country.
Article 1(4) (Saving Clause).
This is a critical provision that reserves the right of the United States to tax its citizens and residents on their worldwide income, regardless of other treaty articles. This clause ensures that a US citizen living in Japan remains subject to US tax on all income, with limited exceptions. The primary relief from double taxation comes from the Foreign Tax Credit, not treaty exemptions.
| Income type | Treaty rate | Statutory rate | Notes |
|---|---|---|---|
| Dividends | 10% | 20.42% (Japan rate for non-residents) | 5% where the beneficial owner is a company holding, directly or indirectly, at least 10% of the voting shares; 0% under Article 10(3) for a company that has held at least 50% of the voting stock for the six months ending on the date entitlement to the dividends is determined and that meets the Article 22 limitation-on-benefits conditions, and for a qualifying pension fund. |
| Interest | 0% | 20.42% (Japan rate for non-residents) | Generally exempt under the protocol signed in 2013, which entered into force on 30 August 2019; certain contingent interest is taxed at 10%. |
| Royalties | 0% | 20.42% (Japan rate for non-residents) | Royalties are exempt from source-country withholding under the treaty. |
The saving clause is a standard feature of US tax treaties. For a US citizen in Japan, it means you must still file a US tax return and report your worldwide income. You cannot use Article 10 to claim you only owe 10% tax on dividends, for example. The main benefit of the treaty for individuals is the framework of resourcing rules for applying foreign tax credits to prevent double taxation.
iDeCo, NISA, and US Tax Implications
Japan's popular tax-advantaged savings and retirement accounts, such as the iDeCo (individual-type Defined Contribution pension plan) and NISA (Nippon Individual Savings Account), create significant complexity for US persons. The IRS does not recognize these accounts as 'qualified' retirement plans under US tax law.
This has several important consequences:
- No US Tax Deferral: Unlike a 401(k) or IRA, any income, dividends, or capital gains generated inside an iDeCo or NISA are generally subject to US tax in the year they are earned, even if they are not distributed. The tax-free or tax-deferred growth offered under Japanese law does not apply for US tax purposes.
- PFIC Reporting: Most investment options within these accounts, such as Japanese mutual funds or ETFs, are considered Passive Foreign Investment Companies (PFICs) by the IRS. Holding PFICs requires filing Form 8621 for each fund, which is a complex form. The default tax treatment for PFICs can be very high unless specific, timely elections are made.
- FBAR and FATCA Reporting: The value of iDeCo and NISA accounts must be included when determining if you meet the filing thresholds for FinCEN Form 114 (FBAR) and IRS Form 8938 (FATCA). These accounts are considered foreign financial accounts and must be reported annually if your aggregate account balances exceed the thresholds.
- Foreign Trust Concerns: There is ongoing discussion and lack of definitive guidance on whether these accounts should be treated as foreign trusts for US tax purposes. If they are, this could trigger a requirement to file Form 3520 (Creation of or Transfers to a Foreign Trust) and Form 3520-A (Annual Information Return of Foreign Trust). While some IRS revenue procedures may provide relief from this burdensome reporting for certain accounts, the situation is not entirely clear and may require professional tax advice.
Investments, property, and capital gains in Japan
Beyond retirement accounts, US citizens in Japan must be mindful of how the US taxes other investments. The most significant issue is the prevalence of Passive Foreign Investment Companies (PFICs). Many, if not most, Japanese-domiciled mutual funds and ETFs sold to retail investors fall into this category. Ownership of a PFIC requires filing Form 8621 and can result in a punitive tax regime unless a timely Mark-to-Market or QEF election is made, which is often difficult or impossible.
For capital gains, the treaty provides that gains from the sale of securities by a resident of one country are generally taxable only in that country. However, because of the saving clause, a US citizen residing in Japan is still fully subject to US tax on all capital gains, worldwide. If you sell Japanese stocks and pay Japanese capital gains tax, you can claim a foreign tax credit for the Japanese tax paid against your US tax liability on that same gain.
US citizens who own a Japanese company face different reporting obligations depending on the entity type. A Kabushiki Kaisha (KK) is always a corporation for US tax purposes (a "per se" corporation under Treas. Reg. § 301.7701-2(b)(8)) and cannot elect otherwise. A Godo Kaisha (GK) is an eligible entity under Treas. Reg. § 301.7701-3: a single-member GK defaults to a disregarded entity (branch treatment) unless its owner files Form 8832 to elect corporate classification. A disregarded GK does not expose the owner to CFC, Subpart F, or GILTI rules; it instead requires Form 8858 annually. If a GK has elected or otherwise holds corporate status, the CFC analysis applies: the company is a CFC only where US shareholders, counting only those who each own 10% or more, together own more than 50% of its vote or value, triggering Form 5471 and potential current US taxation on earnings under Subpart F or GILTI.
Self-employment and companies in Japan
For self-employed US citizens in Japan, the US-Japan Totalization Agreement is a critical document. This agreement, which is separate from the income tax treaty, coordinates social security coverage and contributions for people who work in both countries during their careers.
Its primary benefit for freelancers, contractors, and other self-employed individuals is preventing double social security taxation. Under the agreement a self-employed person is generally covered by the system of the country where they reside, so someone self-employed and resident in Japan contributes to Japan's national pension and health insurance systems and is relieved of US self-employment tax on the same earnings. Where that coverage does not apply, US self-employment tax runs at 15.3% on 92.35% of net earnings, with the 12.4% Social Security portion stopping at the annual wage base ($176,100 for 2025) and the 2.9% Medicare portion uncapped, plus a further 0.9% Additional Medicare Tax on combined Medicare-taxed wages and self-employment income above $200,000 for a single, head-of-household or qualifying-surviving-spouse filer, $250,000 for a joint return, and $125,000 for married filing separately, once net earnings are $400 or more.
To claim this exemption, you must obtain a Certificate of Coverage from the appropriate Japanese social insurance agency. This certificate serves as proof that you are covered by the Japanese system and should be kept with your records to substantiate your exemption from US self-employment tax. It is important to note that the Foreign Earned Income Exclusion (FEIE) does not reduce income subject to self-employment tax, so the Certificate of Coverage is what evidences the coverage that relieves it.
Worked examples
Salaried Employee at a Japanese Tech Company (2025)
Sarah is a US citizen working as a software developer in Tokyo. Her annual salary is JPY 15,000,000. At an exchange rate of 150 JPY to 1 USD, her income is $100,000. She pays approximately JPY 3,500,000 (about $23,333) in Japanese national and local income taxes.
On her US tax return, she has two main options to avoid double taxation on her salary:
- Foreign Earned Income Exclusion (FEIE): If her tax home is in Japan and she meets either the 330-day physical presence test or the bona fide residence test, she can exclude up to the 2025 limit of $130,000 of her foreign earned income. That would reduce the salary included in her US taxable income to zero.
- Foreign Tax Credit (FTC): She can calculate her US tax on the $100,000 income (producing roughly $13,400 in tentative US tax for a single filer taking the 2025 standard deduction; it varies with filing status and deductions) and then claim a credit for the $23,333 in Japanese taxes she paid. The credit is capped by the Form 1116 limitation for the general category, so on these facts it offsets the US tax on the salary and leaves excess credits to carry forward.
The FTC is often the better choice because Japanese income tax rates are high, and claiming the FTC preserves the refundable Additional Child Tax Credit, which electing the FEIE would bar for the whole year under IRC §24(d)(3) regardless of how much income the exclusion removes. Sarah also has a NISA account, so she must determine if the funds inside are PFICs, report any internal gains on her US return, and report the account on her FBAR and Form 8938.
Self-Employed Business Consultant (2025)
David is a US citizen living in Osaka and working as a self-employed marketing consultant for Japanese clients. His net self-employment income for the year is JPY 12,000,000, which is approximately $80,000.
As a resident, David is required to contribute to Japan's National Pension and National Health Insurance systems. Because of the US-Japan Totalization Agreement, he can obtain a Certificate of Coverage from his local Japanese social insurance office. On his US tax return, he reports the $80,000 of income on Schedule C. However, he does not have to pay the 15.3% US self-employment tax (which would have been approximately $11,300) because the Certificate of Coverage proves he is covered by the Japanese system. This is a significant tax savings.
For income tax purposes, he will still owe US income tax on the $80,000 but can use the Foreign Tax Credit for Japanese income taxes paid to offset this liability, likely reducing it to zero.
Retiree with US and Japanese Investments (2025)
Linda is a US citizen retiree living in Kyoto. Her income consists of $40,000 in dividends from a US brokerage account and $10,000 in capital gains from selling some Japanese stocks she owned for several years.
For the $40,000 in US-source dividends, Japan taxes the dividends fully as the residence country. On her US return, Linda reports the full $40,000 in dividends. The treaty provides resourcing rules allowing her to claim a foreign tax credit for the Japanese tax paid on this US-source income to prevent double taxation.
For the $10,000 capital gain on Japanese stocks, she is subject to tax in both countries due to the saving clause. She pays Japanese capital gains tax (e.g., 20.315%, or about $2,031). On her US return, she reports the $10,000 capital gain. She then claims a foreign tax credit for the $2,031 paid to Japan, which directly reduces her US tax on that gain. She must also report her Japanese bank and investment accounts on her FBAR.
Common mistakes for Americans in Japan
- Assuming iDeCo and NISA accounts are tax-deferred or tax-free for US purposes, and failing to report annual internal gains.
- Ignoring the Passive Foreign Investment Company (PFIC) rules for Japanese mutual funds held in NISA, iDeCo, or regular brokerage accounts, leading to a failure to file Form 8621.
- Forgetting to report Japanese retirement, savings, and bank accounts on FinCEN Form 114 (FBAR) and Form 8938.
- Misunderstanding the treaty's 'saving clause' and incorrectly believing that the treaty exempts them from filing a US tax return or reporting their Japanese income.
- A self-employed person paying US self-employment tax when they are covered by the Japanese social security system and eligible for an exemption under the Totalization Agreement.
- Failing to file Form 5471 when owning a significant share of a Japanese corporation (KK or GK), which may be classified as a Controlled Foreign Corporation (CFC).
- Believing that because the treaty eliminates withholding tax on interest (Article 11), the interest income itself does not need to be reported on their US tax return.
- Confusing the income tax treaty with the totalization agreement, which cover separate issues (income tax vs. social security tax).
Japan tax FAQ
Are my Japanese iDeCo or NISA accounts tax-free in the US?
No. The IRS does not recognize the tax-advantaged status of iDeCo and NISA accounts. You must report any dividends, interest, or capital gains earned within these accounts on your US tax return in the year they occur, even if you do not take a distribution. Furthermore, the underlying investments are often PFICs, which require complex reporting on Form 8621.
Do I need to report my Japanese bank accounts to the US government?
Yes, most likely. If the aggregate value of all your foreign financial accounts (including bank, brokerage, iDeCo, and NISA accounts) exceeds $10,000 at any point during the year, you must file FinCEN Form 114 (FBAR). If you have a higher value of assets, you may also need to file IRS Form 8938 with your tax return.
I already pay high income taxes in Japan. Will I be double-taxed by the US?
Generally, no. While you must still file a US tax return, you can claim a Foreign Tax Credit (FTC) for the income taxes you pay to Japan. Since Japanese income tax rates are typically as high or higher than US rates, the FTC often eliminates the US tax on your Japanese-source income. It is the mechanism designed to relieve double taxation, but the Form 1116 limitation and its separate income categories mean it does not always cancel the US tax in full.
What is a PFIC and why do I need to worry about it in Japan?
A PFIC is a Passive Foreign Investment Company. A foreign corporation (including a fund) is a PFIC if it meets either of two tests: 75% or more of its gross income is passive, or at least 50% of its assets produce or are held to produce passive income. Most Japanese mutual funds and ETFs available to retail investors are PFICs. Owning them requires filing the very complex Form 8621, and the default tax rules are extremely unfavorable. It is a major compliance trap for US investors in Japan.
As a self-employed American in Japan, do I owe US Social Security and Medicare taxes?
No, provided you are contributing to the Japanese social security system. The US-Japan Totalization Agreement prevents double social security taxation. You can obtain a Certificate of Coverage from the Japanese authorities to prove your participation and exempt yourself from paying US self-employment taxes.
What is the 'saving clause' in the US-Japan tax treaty?
The saving clause (Article 1, Paragraph 4) is a provision that allows the US to tax its citizens and residents as if the treaty didn't exist. This means you cannot use the treaty's articles to exclude income from your US tax return. Its main purpose is to preserve the US system of worldwide taxation for its citizens. The primary relief from double taxation comes from foreign tax credits, not treaty exemptions.
I started a small Japanese company (a Godo Kaisha). Are there special US filing requirements?
Yes, but the obligations depend on how the Godo Kaisha (GK) is classified for US tax purposes — and that depends on an election you may or may not have made.
A Kabushiki Kaisha (KK) is a "per se" corporation under Treas. Reg. § 301.7701-2(b)(8) and is always treated as a corporation for US tax purposes. A Godo Kaisha (GK) is different: it is an eligible entity under Treas. Reg. § 301.7701-3. A single-member GK defaults to a disregarded entity (treated as a branch of its owner) unless its owner files Form 8832 to elect corporate classification. Many US expats specifically use the single-member GK structure to remain outside the CFC regime.
If the GK is a disregarded entity: It is not a corporation and cannot be a CFC. The owner reports the GK's income and expenses directly on their US return and files Form 8858 (Information Return of US Persons with Respect to Foreign Disregarded Entities) annually. Subpart F and GILTI do not apply.
If the GK has elected or otherwise holds corporate status: The CFC analysis applies. The company is a Controlled Foreign Corporation only if US shareholders who each own 10% or more together own more than 50% of its vote or value. At that threshold, Form 5471 is required annually, and the company's earnings may be subject to current US taxation under Subpart F or GILTI. Failure to file Form 5471 carries significant penalties.
The treaty says 0% tax on interest. Does that mean I don't have to report interest from my Japanese bank account?
No. Tax treaties govern cross-border payments between treaty countries, limiting source-country withholding when interest is paid to a resident of the other country. Because you are a Japanese resident receiving interest from a local Japanese bank, there is no cross-border payment, so the treaty does not limit Japan's domestic 20.315% tax on that interest. Meanwhile, the United States taxes your worldwide interest income under the treaty's saving clause (Article 1, Paragraph 4). You must report the gross interest on your US return and claim a Foreign Tax Credit (Form 1116, passive category) for the Japanese tax paid to prevent double taxation.
Sources and last reviewed
- IRS, Japan Tax Treaty Documents (verified 2026-06-07)
- US Department of the Treasury, Tax Treaty Documents (verified 2026-06-07)
- SSA, US-Japan Totalization Agreement (verified 2026-06-07)
- Japan National Tax Agency (English) (verified 2026-06-07)
- IRS Publication 54, Tax Guide for U.S. Citizens and Resident Aliens Abroad (verified 2026-06-07)
Reviewed by Ilya Fayerman, Esq. (NY Bar) on
Asia depth guide
For filing context specific to Japan in APAC, see the dedicated guide on US Tax Asia, Japan (separate site, complementary content).
Common services needed by expats in Japan
Most Americans abroad in Japan need help with at least one of the following core compliance areas, which frequently interact:
- US expat tax returns, Form 1040 with FEIE, FTC, treaty positions, and any required state returns.
- FBAR reporting, FinCEN Form 114 for foreign financial accounts exceeding $10,000 aggregate at any time during the year.
- Form 8938 (FATCA), IRS disclosure of specified foreign financial assets when thresholds are met.
- Streamlined catch-up filing, For eligible non-willful taxpayers with prior unfiled years.
Related country guides
- US expat tax in South Korea
- US expat tax in Hong Kong
- US expat tax in Singapore
- US expat tax in Thailand
- US expat tax in Taiwan
- US expat tax in Philippines