The 5-Year Rule: How Korea Taxes the Foreign Income of Foreign Residents

외국인 거주자의 과세범위 — 5년 룰과 국외원천소득 신고

 

1. Question

"I'm a foreign national in my third year of working in Korea, so I understand I'm a Korean tax resident. I still own a rented-out flat back home, and I hold overseas brokerage accounts that pay dividends. Last year I transferred part of the rent to my Korean bank account to cover living costs; the rest stayed overseas. I've heard foreigners only pay Korean tax on money they bring into Korea. Is that right? And does anything change once I've been here longer?"

 

📌 The short answer

 

For your first years in Korea, the "5-year rule" narrows what Korea taxes. If your total time as a Korean resident over the past 10 years is 5 years or less, foreign-source income is taxed only to the extent it is paid in Korea or remitted to Korea.

"Only what I bring in" is only half right — and only temporarily. Korean-source income is always fully taxable, remitted foreign income is taxable now, and once you pass the 5-year mark, foreign income becomes taxable whether or not it ever enters Korea.

Foreign income that is taxable generally has to go into your May return, because Korean withholding never touched it. Relief for tax paid abroad is claimed through the foreign tax credit, not by leaving the income out.

The detailed grounds and decision criteria follow below.

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Statutes cited in this post

Abbreviation	Statute (English)	Statute (Korean)
ITA	Income Tax Act	소득세법
ITA Decree	Enforcement Decree of the Income Tax Act	소득세법 시행령

"Art." refers to an article (조) of the statute; numbers in parentheses refer to paragraphs (항) and subparagraphs (호).

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A. Summary of facts

This post is for foreign nationals who are Korean tax residents and who have income arising outside Korea. In brief, a resident is an individual with a domicile (주소) in Korea or a residence (거소) in Korea for 183 days or more (ITA Art. 1-2(1)1) — which covers most foreign nationals living and working here on multi-year contracts. Typical foreign income in question includes:

• rent from a home-country property
• interest and dividends from overseas bank and brokerage accounts
• gains from selling assets located abroad

The question is not whether such residents are taxable in Korea at all — as residents, they are — but how much of that foreign income Korea reaches, and what has to be reported in the May comprehensive income tax return.

B. Issues

• Issue ① Who qualifies for the 5-year rule, and how is the 5 years counted?
• Issue ② What does "paid in Korea or remitted to Korea" mean in practice?
• Issue ③ How is each type of foreign income actually taxed and reported — rental, financial income, and gains on foreign assets?
• Issue ④ How is double taxation relieved when the other country also taxes the income?

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3. Relevant Provisions by Issue

If you are not interested in the statutory text, feel free to skip this section and go straight to 4. Tax Analysis.

A. The 5-year rule (Issues ① and ②) 

Provision	Content
ITA Art. 1-2(1)1·2	A "resident" is an individual with a domicile in Korea, or with a residence in Korea for 183 days or more. A "non-resident" is any individual who is not a resident.
ITA Art. 3(1)	Residents are taxed on all income. However, for a foreign resident whose total period of domicile or residence in Korea, counted over the 10 years before the end of the tax year, is 5 years or less, income arising outside Korea is taxed only to the extent it is paid in Korea or remitted to Korea.
ITA Decree Art. 4(1)·(2)

B. Taxation of foreign income by type (Issue ③) 

Provision	Contents
ITA Art. 12(2)(b)	Rental income of a person owning one house is exempt — but housing with a standard value over KRW 1.2 billion and housing located outside Korea are excluded from the exemption.
ITA Art. 14(3)6	Interest and dividend income totalling KRW 20 million or less is excluded from the aggregated tax base only where the income was withheld under ITA Art. 127.
ITA Art. 70(1)·(2)	A resident with comprehensive income must file from May 1 to May 31 of the following year; this includes cases with separately taxed housing rental income.
ITA Art. 118-2	Gains of a resident on assets located abroad (land, buildings, real estate rights, and certain other assets) are taxable as capital gains — but only for a resident who has kept a domicile or residence in Korea continuously for 5 years or more up to the date of transfer.
ITA Art. 118-6	Foreign tax paid on such foreign-asset gains is relieved by credit (or, alternatively, deduction as necessary expenses).

C. Double taxation relief (Issue ④)

Provision	Content
ITA Art. 57(1)	Where foreign-source income included in comprehensive or retirement income has borne foreign income tax, that foreign tax is credited against Korean tax within a ceiling (Korean tax × foreign-source income ÷ total income).
ITA Art. 57(2)	Excess foreign tax above the ceiling carries forward for up to 10 years; amounts still uncredited at the end of that period may be deducted as necessary expenses.
ITA Art. 57(3)	Tax spared (reduced or exempted) in a treaty country is treated as creditable foreign tax within the limits set by the treaty.

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4. Tax Analysis

Key terms

• Resident (거주자): an individual with a domicile in Korea or a residence here for 183 days or more (ITA Art. 1-2(1)1). The test is where you actually live, not nationality or visa type.
• Foreign-source income (국외원천소득): income arising outside Korea — foreign rent, foreign interest and dividends, gains on foreign assets. Salary for work performed in Korea is not foreign-source, whoever pays it.
• Remittance (송금): bringing the money into Korea — typically a transfer into a Korean account.
• Withholding (원천징수): tax deducted at source by a Korean payer. Foreign payers do not withhold Korean tax, which is why foreign income usually ends up in the May return.
• Foreign tax credit (외국납부세액공제): offsetting foreign income tax against Korean tax on the same income.

Case A. Mr. J, in his third year as a Korean resident, earns rent on a flat abroad. He remitted part of last year's rent to his Korean account; the rest stayed overseas.
→ Direction: Under the 5-year rule, only the remitted portion is taxable in Korea for that year. It goes into his May return as rental (business) income, with a foreign tax credit for any tax paid abroad on that portion.

Case B. Ms. K has been a Korean resident for 7 of the past 10 years. Her overseas accounts earned USD dividends last year, which she never brought into Korea.
→ Direction: The 5-year rule no longer protects her. The dividends are taxable in Korea regardless of remittance, and because no Korean withholding occurred, they are aggregated into her May return even if the amount is small.

A. Who gets the 5-year rule, and how the count works (Issue ①)

The rule applies to a foreign resident — a resident who is not a Korean national — whose total period of domicile or residence in Korea, over the 10 years ending with the last day of the tax year, adds up to 5 years or less (ITA Art. 3(1) proviso).

Three features of the count deserve attention.

It is cumulative, not continuous. Earlier stints in Korea within the 10-year window count toward the 5 years. A person who previously lived in Korea for 3 years, left, and returned 2 years ago has already accumulated 5 years.

It is tested year by year. The 10-year window rolls with each tax year, so a person can qualify in one year and fall outside the rule in the next. The year you cross the threshold, your worldwide foreign income comes fully into scope.

Temporary absences do not interrupt residence. Short trips abroad for clearly temporary purposes count as continued Korean residence (ITA Decree Art. 4(2)), so leaving for holidays does not reset or slow the count.

One caution before moving on: this test in Art. 3(1) is a cumulative count over 10 years. A different, continuous 5-year test appears below for gains on foreign assets — the two are easily confused and work in opposite directions.

B. "Paid in Korea or remitted to Korea" (Issue ②)

While the 5-year rule applies, foreign-source income is taxable only if it is paid in Korea or remitted to Korea (ITA Art. 3(1) proviso). The statute and the Enforcement Decree do not define these terms further, so their application at the margins is a matter of interpretation and individual assessment. The core cases, however, are clear enough:

• foreign income deposited by the payer directly into a Korean account is paid in Korea
• foreign income you transfer from an overseas account into Korea is remitted

The grey zone starts where money moves indirectly — for example, foreign funds used abroad to settle Korean liabilities, or mixed accounts where taxed Korean salary and untaxed foreign income sit together before a transfer. In those situations, what was "remitted" can be disputed, and contemporaneous records are what settle it. Keep foreign-income accounts separate where possible, and keep the paper trail for each transfer: which income it came from, and which year it arose. If a remittance draws on several years' accumulated income, the attribution itself becomes a matter of individual judgment, and professional advice before large transfers is worthwhile.

One boundary is worth stating plainly: this whole framework applies only to genuinely foreign-source income. Salary for work performed in Korea is Korean-source and fully taxable even if an overseas employer pays it into an overseas account — leaving it offshore does not engage the 5-year rule at all.

C. How each type of foreign income is taxed (Issue ③)

Foreign rental income. Once taxable (remitted, or after the 5-year mark), foreign rent is business income in the May return. Note that the one-house exemption does not help here: the exemption for a single owned house expressly excludes housing located outside Korea (ITA Art. 12(2)(b)). Owning only the one flat abroad does not make its rent exempt.

 

Foreign interest and dividends. Korean-paid financial income of KRW 20 million or less normally stays out of the aggregated tax base because it has been withheld at source. That exclusion is written to require withholding under ITA Art. 127 (ITA Art. 14(3)6) — and a foreign bank or broker does not withhold Korean tax. The practical result: taxable foreign interest and dividends are aggregated into the May return regardless of amount, unless they are collected through a Korean intermediary that withholds on them. This is the single most common omission we see in foreign residents' returns.

 

Gains on assets located abroad. Here the law uses a different residency threshold. Capital gains on foreign land, buildings and real estate rights are taxable only for a resident who has maintained a Korean domicile or residence continuously for 5 or more years up to the date of transfer (ITA Art. 118-2). Contrast the two rules directly:

	Art. 3(1) proviso (foreign ordinary income)	Art. 118-2 (foreign asset gains)
Test	Cumulative ≤ 5 years within past 10	Continuous ≥ 5 years up to transfer date
Effect of short residency	Foreign income taxed only if remitted	Foreign-asset gains not taxable at all
Effect of long residency	Worldwide income fully taxable	Foreign-asset gains taxable

So a foreign resident in year 3 who sells a foreign property generally faces no Korean capital gains tax on it, while the same person's remitted foreign rent is taxable. Timing a foreign-asset sale against the continuous 5-year line is therefore a genuine planning point — and one to review with an adviser, since the residency facts themselves can be contested.

Filing mechanics. Whatever the type, taxable foreign income has no Korean withholding history behind it, so the year-end settlement your employer runs on your salary does not cover it. The exemption from filing for those with wages only is lost, and a May comprehensive return is required (ITA Art. 70(1)). Foreign-asset gains, where taxable, follow the capital gains filing track with their own credit rule (ITA Art. 118-6).

D. Double taxation relief (Issue ④)

Foreign income that Korea taxes has usually been taxed where it arose. Korea relieves this through the foreign tax credit: foreign income tax paid or payable on foreign-source income in the aggregated base is credited against Korean tax, up to a ceiling equal to the Korean tax attributable to that foreign income (ITA Art. 57(1)).

Points that matter in practice:

• The credit is claimed in the return. It does not apply automatically; you need proof of the foreign tax (assessments, withholding statements) attached to the May filing.
• Excess credit is not lost immediately. Foreign tax above the ceiling carries forward up to 10 years, and anything still unused at the end of that period may be deducted as necessary expenses (ITA Art. 57(2)).
• Treaty-spared tax can count. Where a treaty partner reduced or exempted its tax, the spared amount is treated as creditable within the treaty's limits (ITA Art. 57(3)).
• While the 5-year rule applies, match the credit to the taxed portion. If only remitted income is taxable in Korea, only the foreign tax attributable to that portion belongs in the credit calculation — attribution needs working papers.

A separate note for completeness: residents holding overseas financial accounts may also have a stand-alone reporting obligation for the accounts themselves under the Adjustment of International Taxes Act, independent of income tax. That regime has its own thresholds and penalties and will be covered in a separate post.

E. Practical management

• Keep a running count of your Korean residence years within the rolling 10-year window, and diarise the year you will cross the 5-year line — your reporting scope changes that year, not gradually.
• Separate accounts: keep foreign-source income away from the accounts you remit from, or document each remittance's source income and year at the time of transfer.
• Collect foreign tax evidence during the year (dividend withholding statements, foreign assessments), not in May.
• Before selling a foreign property, check where you stand against the continuous 5-year test of ITA Art. 118-2 — the answer can be the difference between no Korean tax and a full gains computation.
• If you employ foreign staff, flag to them that year-end settlement covers only their salary; foreign income is their own May filing obligation.

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5. Conclusion

In principle, a foreign resident within the 5-year rule is taxed on foreign-source income only to the extent it is paid in Korea or remitted to Korea, while all Korean-source income remains fully taxable.

The narrowing does not apply, or does not help, in the following cases:

• your cumulative Korean residence over the past 10 years exceeds 5 years — worldwide income is then fully taxable, remitted or not
• the income is Korean-source, such as salary for work performed in Korea, whoever pays it and wherever it is paid
• the income was in fact paid in or remitted to Korea during the year
• the exemption you are counting on excludes foreign items — as the one-house rental exemption excludes overseas housing, and the small-financial-income exclusion requires Korean withholding

On the mitigating side, foreign tax paid on the taxable portion is creditable with a 10-year carryforward, and gains on foreign real estate stay outside Korean tax entirely until you have been continuously resident for 5 years.

The question is not "did I bring the money in" alone — it is "which 5-year test applies to me this year, and which side of it am I on."

If you are approaching either 5-year line, or planning a large remittance or a foreign-asset sale, we recommend a review before acting. Consultations in English are available.

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※ Disclaimer

This post is written to provide general tax information and is not tax advice on any specific matter. Actual tax treatment may vary depending on individual facts, changes in legislation, and the interpretations of the tax authorities. Please consult a professional before making any important decision. The author accepts no responsibility for any consequences arising from reliance on this post.