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US Tax Help for Americans in South Korea
Short answer: Americans in South Korea file a US return on worldwide income, whether they teach, work for a Korean company, work on a base or run a business. All State Tax Resolution, led by Sabih Shafi, an Enrolled Agent, prepares the US side. South Korea has both an income tax treaty and a Social Security agreement with the US, and who pays you decides which rules apply.
Key takeaways
A US citizen or green card holder in South Korea files a US return on worldwide income, and the IRS says the rules are generally the same as at home.
The exclusion is up to $130,000 for 2025 and $132,900 for 2026, per person. It does not cover pay from the US government, pensions or Social Security benefits.
Korea is on the IRS treaty list and has a Social Security agreement with the US. Working for a Korean employer generally puts you under Korean coverage.
Korean accounts can trigger an FBAR above $10,000 combined, and sometimes Form 8938.
If you missed US filings, the streamlined procedures may fit when the failure was not willful.
Do Americans in South Korea have to file a US return?
Yes, in most cases. The IRS says you are taxed on worldwide income from all sources, and the filing rules are generally the same abroad as at home. That applies in Seoul, Busan, Daegu, Jeju or a smaller city, and it applies to a green card holder as well as a citizen.
The regular due date is April 15. If you live outside the US and your main place of business or post of duty is outside the US on that date, you get an automatic two extra months, to June 15, by attaching a statement. Interest on tax you owe still runs from April 15. Form 4868 adds four more months, to October 15, for filing only.
Who pays you matters
In Korea, the first question we ask is who signs your paycheck. The answer changes your US return.
A Korean school or company. Pay for work you do in Korea is foreign earned income, which the exclusion can cover if you have a foreign tax home and meet a residence or 330-day test. English teachers are the classic case.
The US government. The IRS says pay received as a military or civilian employee of the US government or any of its agencies is not foreign earned income. If you work for a US agency in Korea, the exclusion does not apply to that pay.
Yourself. Freelancers and business owners can exclude earned income, but the exclusion does not reduce self-employment tax.
If your employer is a private company, even one that serves US government customers, send us the contract so we can confirm who the employer is before we advise.
Treaty, exclusion and credit
The IRS list of US income tax treaties includes Korea. The IRS also says most income tax treaties contain a saving clause that stops a US citizen or resident from using the treaty to avoid tax on US source income. So the treaty does not replace your US return, and we read the specific articles for your facts instead of assuming.
The foreign earned income exclusion, claimed on Form 2555, leaves up to $130,000 of foreign earnings out of US income tax for 2025, and up to $132,900 for 2026, per person. The physical presence test needs at least 330 full days in foreign countries in any 12 months in a row. The bona fide residence test needs an uninterrupted stay in a foreign country that includes an entire tax year. Either way you also need a tax home abroad, and the IRS says you do not have one while your abode stays in the US.
The foreign tax credit, claimed on Form 1116, reduces US tax by qualifying foreign income taxes. The IRS says you cannot take a credit for tax on income you exclude. The Korean National Tax Service says a Korean resident reports income from all sources, inside and outside Korea, and its English site covers year-end tax settlement. Keep your Korean year-end statements, because we use them to work out the credit. We run both routes and show you which comes out better.
Social Security: the Korea agreement in plain terms
The Social Security Administration lists an agreement with South Korea, in force since 2001. Its purpose is to stop dual Social Security tax on the same earnings. For employees working in Korea, it says:
If a US employer sent you to work in Korea for five years or fewer, you stay in the US system.
If the US employer sent you for more than five years, you were hired in Korea, or you work for a non-US employer, Korean coverage applies.
Whichever system covers you, you need a certificate of coverage from that country to prove the exemption in the other. For the self-employed, coverage follows where you live. Self-employed workers who reside in Korea are assigned Korean coverage, and a certificate copy goes with the US return every year. If US coverage applies instead, the self-employed owe US self-employment tax, and the exclusion does not reduce it.
Won, bank accounts and FATCA
You must report amounts on a US return in US dollars. The IRS says you generally use the exchange rate in effect when you receive, pay or accrue the item, and it generally accepts any posted rate used consistently. The IRS yearly average rate table lists the South Korean won.
FBAR (FinCEN Form 114). FinCEN says you must file if your foreign financial accounts together exceed $10,000 at any time in the calendar year. It is filed online with FinCEN, not with your return, and due April 15 with an automatic extension to October 15.
Form 8938. It is attached to your return. If you live abroad by the IRS definition, the thresholds are above $200,000 on the last day of the year or $300,000 at any time for a return that is not joint, and $400,000 or $600,000 for a joint return.
The US Treasury lists an intergovernmental agreement with South Korea as in force. The IRS says FATCA generally requires foreign financial institutions to report on assets held by their US account holders. Treat your Korean accounts as visible to the IRS.
Behind on US filing from South Korea?
The streamlined foreign offshore procedures are for people abroad whose failures were non-willful, meaning negligence, inadvertence, mistake or a good faith misunderstanding of the law. The IRS asks for returns for the most recent three years with a passed due date, FBARs for the most recent six years, all tax and interest paid with the returns, and Form 14653 certifying non-willful conduct. You need no US abode and at least 330 full days outside the US in one of the three years.
The IRS says a filer who qualifies and follows the instructions is not subject to failure-to-file, failure-to-pay, accuracy-related, information return or FBAR penalties, unless an exam finds fraud or a willful FBAR violation. A civil exam or criminal investigation already underway rules the procedures out. If your conduct may have been willful, talk to us before filing.
State taxes after you move
California's Franchise Tax Board treats you as a resident if you are domiciled in California but outside the state for a temporary or transitory purpose. Other states have their own tests. We check your last state's rules instead of guessing.
How we help
I am Sabih Shafi, an IRS Enrolled Agent, federally licensed to represent taxpayers before the IRS in all 50 states. We work by phone and video, in English or Spanish, with Americans anywhere in South Korea.
Your US return: Form 1040 with Form 2555 or Form 1116, run both ways.
Employer check: we read your contract to see whether your pay can be excluded.
Foreign account reports: FBAR and Form 8938 checks.
Missed years: several unfiled years prepared, with a straight answer on whether streamlined fits.
A flat fee quoted in writing before work starts.
Frequently Asked Questions
I teach English in Korea. Do I file a US return?
Yes, if you are a US citizen or green card holder with income above the filing threshold. Pay for teaching in Korea is foreign earned income, which the exclusion can cover if you meet the tests.
I work for the US government in Korea. Can I use the exclusion?
Not on that pay. The IRS says pay received as a military or civilian employee of the US government or any of its agencies is not foreign earned income.
Does Korea have a tax treaty with the US?
Yes. Korea is on the IRS list of US income tax treaties. Most treaties contain a saving clause, so we check the specific article for your income.
Does the US have a Social Security agreement with South Korea?
Yes, in force since 2001. A Korean employer generally puts you under Korean coverage, and a US employer that sent you for five years or fewer keeps you in the US system.
Do I need an FBAR for my Korean bank account?
If all your foreign accounts together exceed $10,000 at any time in the year, yes. Balances are added across accounts.
Can you prepare my Korean tax return?
No. We prepare the US side only, and work with the figures your Korean preparer or employer gives us.
General information, not tax advice for your situation.
Related Reading
Talk to an Enrolled Agent
This article is general information, not individual tax advice. If you want to talk through your own IRS or state balance, book a free 20-minute review or call or text us directly.
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