Foreign companies in Korea
When does a foreign company's Korean branch file its corporate tax return?
In short A Korean branch files like a Korean company: the annual corporate tax return is due within three months after the fiscal year-end (March 31 for a December year-end), and an interim prepayment is due within two months after the first six months (August 31 for a December year-end). If the tax treaty allows it, a branch profits tax is added on top.
Key points
| Annual return | Within 3 months after the fiscal year-end (Art. 60, applied by Art. 97(1)) |
|---|---|
| December year-end | Due March 31 |
| Interim prepayment | Within 2 months after the first 6 months of the year (Art. 63, applied by Art. 97(1)); August 31 for a December year-end |
| Extension | Possible with tax office approval for specific reasons, with interest added (Art. 97(2), (3)) |
| Branch profits tax | Only if the tax treaty allows it; 20% under domestic law or the treaty rate; amounts reinvested in Korea can be deducted (Art. 96) |
The branch is taxed like a Korean company
A branch is a fixed place of business in Korea, so it is a permanent establishment (Corporate Tax Act Article 94(1), (2)). Its Korean-source business income is taxed, and the filing, payment, interim prepayment and penalty rules for Korean companies apply to it (Article 97(1)).
Annual return and interim prepayment
The annual return is due within three months after the end of the branch's fiscal year (Article 60). For a December year-end that is March 31. If the fiscal year is longer than six months, an interim prepayment for the first six months is due within two months after that period ends (Article 63(2), (3)), which is August 31 for a December year-end.
If the return cannot be filed on time for reasons set by decree, the deadline can be extended with approval, but interest is added for the extra days (Article 97(2), (3)).
Branch profits tax
On top of corporate tax, a branch may owe a branch profits tax on its after-tax profits, but only when the tax treaty between Korea and the head office country allows it (Article 96(1)). The rate is 20% under domestic law (Article 98(1)2) or the rate set in the treaty, and amounts the branch reinvests in Korea are deducted from the base (Article 96(2), (3)). We check the treaty before the first return.
FAQ
Is the branch's fiscal year the same as the head office's?
It is the fiscal year the branch reported to the tax office. Tell us the year-end first, because every deadline is counted from it.
Does the branch also file local income tax?
Yes. Local corporate income tax is filed separately with the local government. We prepare both returns together.
Can the branch pay the interim prepayment in instalments?
Yes, if the interim tax exceeds KRW 10 million, part of it can be paid later under the instalment rule (Article 63(4)).
Sources
- Corporate Tax Act Art. 60 (filing within 3 months)
- Corporate Tax Act Art. 63 (interim prepayment)
- Corporate Tax Act Art. 96 (branch profits tax)
- Corporate Tax Act Art. 97 (foreign corporations: filing, extension)
Checked 2026-11-04. Treaty rates and individual facts change the answer, so please confirm your case with us.
More questions in English
Seojin Tax Corporation, Yeouido, Seoul. Registered tax accountant No. 9105103. Previously in the international tax team at Hana Tax Corporation (2022 to 2024). Statutory references were checked against the official Korean law database on 2026-11-04.
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