Can I Be a Tax Resident in Both the U.S. and Korea? — Dual Residency
미국과 한국의 이중 세법상 거주자 — 2026 한국 세법 개정 반영

Overview — What Dual Residency Means 이중 거주자의 의미

Yes — a person can be a tax resident of both the United States and South Korea simultaneously. This is called "dual residency," and it is common for Korean nationals working in the U.S., Korean-Americans spending significant time in Korea, and green card holders who live or work in Korea.

U.S. Tax Residency Rules 미국 세법상 거주자 판정

The U.S. uses two independent tests. Meeting either test makes a person a U.S. tax resident for the entire calendar year (or from the residency starting date in a dual-status year).

Korean Tax Residency Rules — 2026 Changes 한국 세법상 거주자 — 2026 개정

South Korea determines tax residency based on domicile (주소) or place of residence (거소). Korean tax residents are subject to worldwide income taxation; non-residents pay tax only on Korean-source income.

When Dual Residency Occurs 이중 거주자가 되는 경우

Dual residency arises when a person simultaneously meets U.S. residency criteria (Green Card Test or SPT) and Korean residency criteria (domicile, 183-day, or constructive residency). The following situations commonly produce dual residency:

U.S.–Korea Tax Treaty Tie-Breaker 미한 조세조약 거주지 결정

Article 3 of the U.S.–Korea Income Tax Treaty provides a "tie-breaker" mechanism for determining a single country of treaty residence when a person qualifies as a tax resident of both countries under their respective domestic laws. The tie-breaker is applied sequentially — each test is applied only if the preceding test does not resolve the question.

Claiming Treaty Tie-Breaker — Form 8833 (U.S. Side)

• To claim treaty non-resident status in the U.S. under the tie-breaker, file Form 8833(Treaty-Based Return Position Disclosure) with the U.S. tax return. Disclose the treaty article, the factual basis for the claim, and the treaty country of residence.
• A $1,000 penalty applies for failure to file Form 8833 when required. The claim is not self-executing — IRS reviews the factual basis.

Treaty Limits — FBAR Still Applies 조약 비거주자 주장의 한계

Claiming treaty non-resident status under the tie-breaker does not eliminate all U.S. compliance obligations. The treaty affects income tax treatment — but several reporting obligations persist regardless of treaty position.

Foreign Tax Credit — Avoiding Double Taxation 외국납부세액공제 이중과세 방지

When both the U.S. and Korea tax the same income, the Foreign Tax Credit (FTC) is the primary mechanism for eliminating or reducing double taxation. Both countries provide an FTC — Korea taxes paid can credit against U.S. tax on the same income, and U.S. taxes paid can credit against Korean tax on the same income.

U.S. Foreign Tax Credit — Form 1116

• Dollar-for-dollar credit: Korean income tax paid on Korean-source income is creditable against U.S. tax on the same income, dollar-for-dollar. For example: $30,000 in Korean income taxes paid on a Korean salary credits directly against the U.S. income tax liability on that same Korean salary.
• Limitation — foreign tax credit cannot exceed U.S. tax on foreign income: The credit is limited to the proportional U.S. tax on foreign-source income. Excess credits carry back 1 year and forward 10 years.
• Passive vs. general basket: FTC is calculated separately for "passive income" (dividends, interest, royalties, capital gains) and "general income" (wages, business income). Korean salary is general basket; Korean investment income is passive basket. The two baskets cannot cross-apply.
• Korean rates are generally comparable to U.S. rates: Korea's top marginal rate is 45% (plus local income tax ~4.4% = ~49.5% effective top rate). U.S. rates are 37% federal. For Korean residents paying at Korean rates on Korean income, the FTC usually eliminates most or all U.S. tax on that Korean income — since the Korean tax paid typically exceeds the U.S. tax owed on the same income.

Korean Foreign Tax Credit — 외국납부세액공제

• Korea also provides a foreign tax credit for foreign taxes paid on foreign-source income. U.S. taxes paid on U.S.-source income (wages, capital gains, dividends) can be credited against Korean tax on the same income when Korea has taxing rights under the treaty.
• The Korean FTC calculation follows similar limitation rules — the credit cannot exceed the Korean tax on the foreign-source income.

FEIE — Option for U.S. Citizens Living in Korea 해외근로소득공제 — 재한 미국 시민권자

U.S. citizens and lawful permanent residents who live and work in Korea may choose between the Foreign Tax Credit (FTC) and the Foreign Earned Income Exclusion (FEIE) to reduce U.S. tax on Korean employment income. The FEIE excludes a specified amount of foreign earned income from U.S. gross income — rather than crediting foreign taxes paid.

• 2026 FEIE exclusion amount: $132,900(indexed for inflation from $130,000 in 2025). Applies to wages and self-employment income earned in a foreign country — not to investment income, rental income, or passive income.
• Qualification — Physical Presence Test: Must be present outside the U.S. for at least 330 full days in any 12-month period beginning or ending in the tax year. Days in the U.S. for any reason break the 330-day count.
• Qualification — Bona Fide Residence Test: Alternatively, must be a bona fide resident of a foreign country for an uninterrupted period that includes an entire tax year.
• FEIE or FTC — not both on the same income: The FEIE and FTC cannot both apply to the same dollars of excluded income. For most U.S. citizens in Korea — where Korean tax rates often exceed U.S. rates — the FTC is generally more advantageous than the FEIE, because excess Korean taxes can create carryforward FTCs while the FEIE simply excludes income without preserving any credit benefit.
• FEIE does not reduce FBAR or Korean reporting obligations.

Reporting Requirements — Both Countries 양국 신고 의무 비교

4 Real Scenarios — Fully Analyzed 실제 사례 4개

Common Mistakes 자주 발생하는 오류

• 1 Green card holders not filing U.S. taxes while living in Korea, assuming Korean tax compliance is sufficient. The green card creates a permanent U.S. tax resident status that exists independently of Korean tax residency. Both obligations must be met simultaneously. Korean tax payments do not substitute for or satisfy U.S. filing requirements — they only reduce U.S. tax through the Foreign Tax Credit.
• 2 Not knowing about the new 2026 Korean cross-year 183-day rule. Korean-Americans who split their year between the U.S. and Korea — previously safe from Korean residency if they stayed fewer than 183 days in a single calendar year — may now be Korean tax residents under the new rule if their consecutive Korea presence spans a December 31 year-end and totals 183+ days across two years. Extended family visits, sabbaticals, and "semi-retirement in Korea" arrangements require new analysis under the 2026 amendment.
• 3 Filing Form 8833 as a green card holder without immigration counsel. The immigration risk of claiming treaty non-residency while holding a green card cannot be overstated. A treaty-based non-resident claim is a written statement filed with the IRS that USCIS can access — it is evidence that the green card holder does not consider the U.S. their primary residence. This can be used to deny re-entry or initiate abandonment proceedings. Always involve an immigration attorney before any Form 8833 filing.
• 4 Assuming the treaty tie-breaker eliminates FBAR and FATCA obligations. The treaty affects income tax treatment — it does not affect Bank Secrecy Act FBAR requirements. A person who claims Korean treaty residency still owes FBAR reporting for all foreign financial accounts (including Korean accounts) if they hold U.S. person status under the Bank Secrecy Act (which includes all green card holders and citizens regardless of treaty position).
• 5 Not using the Foreign Tax Credit — paying full income tax to both countries on the same income. Dual residents who do not file Form 1116 (U.S. FTC) or claim the Korean equivalent credit effectively pay full income tax twice on the same earnings. The FTC is the primary mechanism for eliminating this double taxation and is almost always applicable when income is taxed by both countries.
• 6 Not understanding that both arrival and departure days count in Korea's 183-day calculation. Korea's 183-day residency test counts both the day of arrival and the day of departure as full days of Korean presence. A person who arrives July 1 and departs December 31 has been present for 184 days (July 1 through December 31 inclusive) — meeting the Korean 183-day threshold by 1 day.
• 7 Not reporting the 해외금융계좌 (Korean overseas account reporting) as Korean residents with U.S. accounts. Korean tax residents who have foreign financial accounts (including U.S. bank or brokerage accounts) with aggregate balances exceeding 50 million KRW (approximately $37,000) at any point during the year must file the overseas financial account report with the NTS by June 30. Korean residents with U.S. investment accounts, 401(k) balances accessible, or U.S. bank accounts may be subject to this Korean reporting obligation.
• 8 Missing the new 2026 Korean overseas trust reporting requirement. Korean tax residents who established or maintained any overseas trust at any point during 2025 must file the new "Overseas Trust Statement" with the NTS by June 30, 2026. This is a brand-new requirement under the 2024 Korean Tax Law Amendment — it affects Korean residents with U.S. living trusts, U.S. estate planning trusts, offshore account structures, or any other foreign trust arrangement.

Hanmi CPA Insight