U.S. citizens and Green Card holders are required to report worldwide income to the IRS, regardless of their country of residence.
This means that even if you work a job or run a business in Korea, you must file a U.S. tax return. Paying taxes in Korea does not exempt you from U.S. tax reporting obligations.
Fortunately, U.S. tax law provides mechanisms like the Foreign Tax Credit (FTC), which allows you to reduce your U.S. tax liability by the amount of taxes already paid in Korea.
1️⃣ Employees vs. Self-Employed: Differences in Required Documentation
The type of income you earn in Korea determines the documentation you must submit to the IRS.
Employees (Withholding Income)
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Withholding method: Your employer automatically deducts income tax and local taxes from your salary.
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Required documents: Form showing income tax withholding (근로소득 원천징수영수증).
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Ease of reporting: A single withholding statement usually suffices to prove annual income and tax paid.
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IRS submission: You can claim the Foreign Tax Credit using Form 1116.
Self-Employed (Business or Freelance Income)
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Reporting method: Self-employed individuals file and pay their Comprehensive Income Tax to the Korean tax authorities annually (typically by May).
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Required documents:
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Certificate of Income Amount – verifies total annual income and tax paid.
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Copy of Comprehensive Income Tax Return – shows total income and tax calculations.
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Payment confirmation or bank payment receipt – proves actual tax payment.
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Key difference: While employees rely on their employer to certify tax payments, self-employed individuals must provide multiple documents to prove income and tax payments themselves.
2️⃣ Key IRS Forms and Considerations
Even if you earned income in Korea, the following forms are essential for U.S. tax reporting:
| Form | Name | Purpose |
|---|---|---|
| Form 1040 | U.S. Individual Income Tax Return | Reports total worldwide income |
| Schedule C | Profit or Loss From Business | Reports business income and expenses for self-employed individuals |
| Form 1116 | Foreign Tax Credit | Claims taxes paid in Korea to avoid double taxation |
⚠️ Self-employed considerations:
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If your income exceeds a certain threshold, you may need to pay Self-Employment Tax (Social Security and Medicare taxes in the U.S.)
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This is separate from Korean National Pension and Health Insurance
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Check the U.S.-Korea Totalization Agreement to avoid double contributions
📎 Submission of Korean-language documents:
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Korean documents are valid for IRS submission
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Prepare English translations in case the IRS requests them
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Keep all tax records for at least three years
3️⃣ Checklist for Successful U.S. Tax Filing
| Type | Required Documents |
|---|---|
| Self-Employed | Copy of Comprehensive Income Tax Return, Certificate of Income Amount, Payment confirmation or bank receipt |
| Employee | Income withholding statement |
| Common | Foreign bank account information (FBAR, Form 8938), English translations of all submitted documents |
Summary:
U.S. citizens and Green Card holders living in Korea must navigate both U.S. and Korean tax laws.
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Employees have relatively simple documentation.
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Self-employed individuals must provide multiple proofs of income and tax payments.
To avoid double taxation and ensure accurate reporting, it is strongly recommended to consult a U.S. tax professional (CPA or EA).