US filing basics for Americans in South Korea
Living in South Korea does not terminate your U.S. federal income tax obligations. U.S. citizens, green-card holders, and certain long-term residents are taxed on worldwide income on a citizenship or residency basis, regardless of where the income is earned or where you reside. You generally must file Form 1040 (or 1040-SR) when gross income exceeds the annual IRS filing threshold, typically $15,000 to $30,000 or more depending on filing status, age, and dependency for recent tax years (exact amounts published in IRS Rev. Proc. documents and inflation-adjusted). Even if no tax is ultimately due after credits and exclusions, filing is usually required to claim benefits such as the Foreign Earned Income Exclusion (FEIE) under IRC §911 (up to $130,000 for tax year 2025 per IRS Rev. Proc. 2024-40) or the Foreign Tax Credit (FTC) for taxes paid to South Korea authorities.
US tax treaty with South Korea
The United States has an income tax treaty with South Korea for many common issues, treaty articles must be applied to your facts.
Local considerations in South Korea
Treaty positions often matter for pensions and cross-border employment packages; FBAR still applies to Korean bank accounts.
Asia depth guide
For filing context specific to South Korea in APAC, see the dedicated guide on US Tax Asia, South Korea (separate site, complementary content).
Common services needed by expats in South Korea
Most Americans abroad in South Korea 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.