--- title: "US tax for Americans in South Korea | Expat Tax Abroad" url: https://expattaxabroad.com/insights/us-tax-americans-in-south-korea/ description: "Korean rates and a 19% flat election decide which route wins for Americans in Korea, and the treaty's teaching article is narrower than it is claimed." lang: en --- Skip to content IRS Enrolled Agent · One preparer, every return 48 country guides 48 guides (https://expattaxabroad.com/countries/) Verify at IRS.gov: https://irs.treasury.gov/rpo/rpo.jsf Facebook: https://www.facebook.com/people/Jorge-I-Rivas-ExpatTax/61572578032002/ Instagram: https://www.instagram.com/jrivas0013/ LinkedIn: https://www.linkedin.com/in/jorgeirivas1186sm X: https://x.com/jrivas0013 Filing rules · 22 September 2026 # US tax for Americans in South Korea Korean income tax is progressive to 45% with a local surtax on top, and there is both a US–Korea income tax treaty and a totalization agreement. For most Americans working here the foreign tax credit beats the Foreign Earned Income Exclusion — but a first-year teacher and a long-serving engineer can land on opposite answers, and the flat-rate election is part of why. Image: A treaty and a totalization agreement both in place, with the reminder that the credit and the exclusion are a comparison rather than a default. (https://expattaxabroad.com/features/art-korea-1600.webp) Image: Jorge I. Rivas, EA (https://expattaxabroad.com/_astro/jorge-rivas-avatar.BkTc9hQv_ZqNxAY.webp) Jorge I. Rivas, EA Enrolled Agent · 7 minutes to read ## A treaty and a totalization agreement, doing separate jobs The US–Korea income tax treaty addresses double income tax; the totalization agreement addresses double social security by assigning your coverage to one system. An American on a Korean payroll with Korean coverage generally escapes US self-employment tax on that work, and a certificate of coverage is the evidence rather than an assumption. ## The teaching article is narrow, and it is claimed far too widely The treaty's teaching and research provision is the single most over-claimed position I see on Korean returns. It is narrow in scope, time-limited, and aimed at a particular kind of invited academic engagement. It does not exempt an ordinary school or hagwon salary, and claiming it where it does not apply creates a position that has to be defended rather than simply filed. The exclusion or the credit is what actually handles a teaching salary — and for a first-year arrival, the exclusion often wins outright. ## The 19% flat election, and what it does to your credit A foreign worker in Korea can elect a flat national rate of 19% on employment income — around 20.9% with the local surtax — instead of the progressive table, for up to twenty years from the start of Korean employment, provided that employment began by the end of December 2026. Choosing it gives up Korean deductions and credits, and it applies to employment income only. On the US side the election is not neutral. A lower Korean rate means less Korean tax paid, which means a smaller foreign tax credit — and for a high earner that can turn a year in which the credit covered everything into a year with US tax to pay. The Korean saving and the US cost have to be weighed together rather than separately. ## First-year arrivals: the exclusion often wins Someone who arrives mid-year on a teaching contract is taxed lightly in Korea for those first months, which leaves little Korean tax to credit. The Foreign Earned Income Exclusion, $130,000 for tax year 2025, frequently covers the whole of that part-year salary and produces a cleaner result than Form 1116 would. That reverses as income and Korean tax rise. It is a genuine year-by-year comparison, which is why a default answer is the wrong answer here more often than in most countries. ## Retirement allowance at the end of a contract Korean law entitles an employee with at least a year of continuous service to a retirement allowance of roughly thirty days' average wage for each year worked. Korea taxes it under a separate regime from ordinary salary; the US treats it as compensation for services performed abroad, attributed to the years in which it was earned. Because the two systems tax it differently and often in different years, it is the item most likely to produce a credit-timing mismatch on a Korean return. ## A worked example, tax year 2025 A single American engineer employed in Seoul on salary equivalent to $135,000, with Korean income tax and local surtax of $28,350 for the year, claiming the credit. | Salary | $135,000 | | --- | --- | | Korean income tax and local surtax paid | $28,350 | | US taxable income after the standard deduction | $119,250 | | US income tax before the credit | $21,467 | | Foreign tax credit allowed | $21,467 | | US income tax after the credit | $0 | | Excess credit carried forward | $6,883 | Korean tax of $28,350 exceeds the $21,467 of US tax on the same income, so the credit covers it and $6,883 carries forward. Had the same person elected the 19% flat rate, Korean tax would have been lower, the credit smaller, and the US result worse — which is the comparison the election actually turns on. Sources: IRC §901 and §904; IRS Form 1116 instructions; Rev. Proc. 2025-32. Scroll the table sideways | Fact | Position | | --- | --- | | US income tax treaty | Yes | | Totalization agreement | Yes | | Local income tax | Progressive to 45%, plus a local surtax | | Self-employment tax (SECA) | Relieved where the agreement covers you | | FBAR threshold | $10,000 aggregate, any point in the year | Sources IRC §901, §904, §911 and §1401; US–Korea income tax treaty, including the teaching and research article; US–Korea totalization agreement; Korean flat-rate election for foreign workers; Korean Labor Standards Act on retirement allowance; IRS Publication 54; IRS Publication 514; Rev. Proc. 2025-32; 31 CFR 1010.350. US figures are tax year 2025. Checked 22 September 2026. Change log 22 September 2026 First published South Korea — full country guide →: https://expattaxabroad.com/countries/south-korea/ Expat tax returns →: https://expattaxabroad.com/services/expat-tax-returns/ FBAR / FATCA compliance →: https://expattaxabroad.com/services/fbar-fatca-compliance/ Treaty & totalization matrix →: https://expattaxabroad.com/tools/treaty-totalization-matrix/ Streamlined catch-up filing →: https://expattaxabroad.com/services/streamlined-catch-up-filing/ Home →: https://expattaxabroad.com/ All insights →: https://expattaxabroad.com/insights/ ## Questions Americans in South Korea ask ### I teach in Korea. Is my salary exempt under the treaty? Almost certainly not. The teaching and research article is narrow and time-limited, and it does not exempt an ordinary school or hagwon salary. The exclusion or the credit is what handles a teaching salary, and for a first-year arrival the exclusion often wins. ### Should I take the 19% flat-rate election? Only after looking at both sides. It lowers Korean tax, which lowers the foreign tax credit available on the US return — so a Korean saving can produce a US bill. It applies to employment income only, runs up to twenty years from the start of Korean employment, and requires that employment to have begun by the end of December 2026. ### Does the totalization agreement remove my self-employment tax? Where it assigns your coverage to the Korean system, yes. That needs a certificate of coverage rather than an assumption, and it is one of the first things worth checking for anyone invoicing for their own services. ### How is my Korean retirement allowance taxed? Korea taxes it under a separate regime from salary. The US treats it as compensation for services performed abroad, attributed to the years it was earned — which is why it so often produces a timing mismatch between the two countries' taxes. ### I have not filed for several years while in Korea. 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. ## Teaching or working in Korea? Fifteen minutes settles whether the credit or the exclusion fits, and whether the flat election helps or hurts your US return. Book a 15-minute call: https://expattaxabroad.com/book/ Complete return $599 Prepared and signed by an Enrolled Agent Book a call (https://expattaxabroad.com/book/) ## Structured data ```json { "@context": "https://schema.org", "@graph": [ { "@type": "Person", "@id": "https://expattaxabroad.com/#jorge", "name": "Jorge I. Rivas", "honorificSuffix": "EA", "jobTitle": "Enrolled Agent", "description": "IRS Enrolled Agent specialising exclusively in US tax for Americans living abroad. 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