US tax for Americans in Japan
Japan is the opposite of a Gulf posting. National income tax reaches 45%, inhabitant tax adds around 10% on top, and there is both a US–Japan income tax treaty and a totalization agreement. That combination usually makes the foreign tax credit the better route — and it leaves two Japanese products, the NISA and the pension lump-sum withdrawal, to handle carefully.
Both instruments are in place, and they do different jobs
There is a US–Japan income tax treaty and a US–Japan totalization agreement. The treaty addresses double income tax and gives the rules for which country taxes what; the totalization agreement addresses double social security, assigning your coverage to one system rather than both. Having one is not having the other, and the questions they answer never overlap.
What neither of them does is remove the filing obligation. Citizenship decides that, so the return is due whatever Japan has already taken.
Why the credit usually beats the exclusion here
National income tax runs to 45% and inhabitant tax adds roughly 10%, which puts the effective Japanese rate on a professional salary well above the US rate on the same income. Form 1116 therefore tends to wipe out the US liability completely and leave excess credits to carry forward — up to ten years, against future foreign-source income.
There is a second reason to prefer it. Income excluded under the Foreign Earned Income Exclusion is not compensation for IRA purposes, so a year run entirely through the exclusion can leave you unable to contribute to a retirement account at all. The credit route keeps that door open.
Inhabitant tax lands in a different US year
Inhabitant tax is assessed on the previous year's income and billed from the following June. The Japanese tax you pay during a calendar year therefore relates to a different year's income than the US return you are filing, which is a timing mismatch rather than a rate problem.
It matters because the credit is claimed either when the foreign tax is paid or when it accrues, and the choice between those methods is effectively permanent once made. Getting it right in the first year filed from Japan saves years of reconciliation afterwards.
A NISA is not tax-free to the IRS
Japan's NISA is a tax-free wrapper under Japanese law and nothing in the treaty extends that treatment to the United States. Dividends and gains inside it are ordinary US taxable income, reported year by year.
Worse, the funds usually held inside one are foreign mutual funds — passive foreign investment companies for US purposes. That brings Form 8621, and under the default method the tax on a disposal is computed at the highest ordinary rate for the years the holding was owned, with an interest charge on top. The wrapper that saves Japanese tax is frequently the most expensive thing on the US return.
Leaving Japan: the lump-sum withdrawal payment
Someone who leaves Japan after contributing to the pension system can claim a lump-sum withdrawal payment, which Japan pays net of withholding. On the US side it is neither tax-free nor automatically covered by the exclusion — it is a pension distribution, characterised on its own facts, and the Japanese tax withheld on it is a credit question rather than the end of the matter.
Claiming it also interacts with the totalization agreement, because periods refunded are periods that no longer count toward Japanese benefits. That is a decision worth taking deliberately rather than at the airport.
A worked example, tax year 2025
A single American employed in Tokyo on ¥-denominated salary equivalent to $150,000, with Japanese national and inhabitant tax of $45,000 for the year, claiming the foreign tax credit rather than the exclusion.
Scroll the table sideways
IRC §901, §904, §911 and §1401; US–Japan income tax treaty and protocol; US–Japan totalization agreement; IRS Publication 54; IRS Publication 514; IRS Form 1116 and Form 8621 instructions; Rev. Proc. 2025-32; 31 CFR 1010.350. US figures are tax year 2025; the standard deduction used is the 2025 amount as raised in 2025. Checked 22 September 2026.
Questions Americans in Japan ask
Should I use the foreign tax credit or the exclusion in Japan?
Usually the credit. Japanese national and inhabitant tax together generally exceed US tax on the same income, so Form 1116 removes the US liability and leaves credits to carry forward. It is still a comparison rather than a rule — a part-year arrival taxed lightly in Japan can come out the other way.
Is my NISA tax-free on the US return?
No. The wrapper is Japanese, and nothing in the treaty makes it tax-free to the United States. The income inside is reported year by year, and the funds held in one are usually PFICs, which brings Form 8621 and a harsher default calculation.
Does the totalization agreement remove my self-employment tax?
Where it assigns your coverage to the Japanese system, yes — and a certificate of coverage is the evidence for it. Without that assignment, 15.3% US self-employment tax applies to net self-employment earnings.
Why does my Japanese tax never match my US tax year?
Inhabitant tax is assessed on last year's income and billed from the following June, so the payments fall in a different year from the income they relate to. Whether you claim credits when paid or when accrued decides how that is handled, and the choice is effectively permanent.
I have not filed for several years while in Japan. What now?
If the failure was non-willful — which describes most people in this position — the Streamlined Foreign Offshore Procedures waive the failure-to-file, failure-to-pay and FBAR penalties: three years of returns, six years of FBARs, and Form 14653.
Filing from Japan?
Twenty minutes settles whether the credit or the exclusion fits your year, and what your NISA is actually doing on the return.