Chapter Key Takeaways
| Tax Year & Filing Period | 2025 Tax Year (Jan 1 – Dec 31, 2025) / Filing: May 1 – May 31, 2026 |
|---|---|
| Who Must File | Foreign tax residents & non-residents with business, 3.3% freelance, multi-job, or rental income in Korea |
| Exempt from May Filing | Wage earners with only one employer whose year-end tax settlement (연말정산) was fully finalized |
| Primary Documents | Withholding Tax Receipt (원천징수영수증), Alien Registration Card (ARC), expense receipts, bank account info |
| Filing Method | Hometax online portal (www.hometax.go.kr), local district tax office, or certified tax agency (일공삼택스) |
| Refund Timeline | Approved tax refunds are deposited directly into taxpayer's Korean bank account in late June to early July |
| Failure to File Penalty | 20% non-filing penalty tax (40% for fraud) + 0.022% per day late-payment interest |
1. Who Must File Global Income Tax in May 2026?
Under Korea's Income Tax Act (소득세법 제70조), individuals who have earned taxable income during the calendar year 2025 (January 1 to December 31) must combine their taxable income from all sources and file a Global Income Tax Return (종합소득세 과세표준확정신고) between May 1 and May 31, 2026.
Foreign nationals are subject to the same tax filing obligations as Korean citizens. You are required to file if you fall under any of the following categories:
- 3.3% Freelancers & Independent Contractors: Foreign instructors, translators, models, consultants, software engineers, and artists who had 3.3% tax withheld at source.
- Registered Business Owners: Foreigners operating a sole proprietorship, restaurant, import-export shop, or e-commerce store in Korea.
- Multiple Income Sources: Foreigners who changed jobs during 2025 without combining their income, or who earned both employment salary and freelance/business income simultaneously.
- Real Estate Rental & Financial Income: Housing rental income exceeding 20 million KRW (or separate taxation choice) or combined interest/dividends exceeding 20 million KRW.
- Missed Year-End Settlement: Employees who failed to submit year-end tax deduction documents (연말정산) to their Korean employer in January/February.
Foreign employees who earned only wage and salary income from a single Korean employer and whose employer successfully completed the Year-End Tax Settlement (연말정산) in February 2026 are exempt from filing a separate May tax return, unless they have other business or overseas income to report.
2. Statutory Filing Period, Deadlines & Methods
The statutory filing and payment window for 2025 global income tax is May 1, 2026 to May 31, 2026 (extended to the next business day if May 31 falls on a weekend or public holiday).
| Filing Channel | Procedure | Considerations for Foreigners |
|---|---|---|
| 103Tax Certified Agency (일공삼택스) | Professional review by Kwon Ji-hyun, Korean certified tax accountant. End-to-end filing, deduction optimization & refund maximization. | Recommended: Overcomes language barriers, optimizes expense deductions, and avoids costly penalty notices. |
| NTS Hometax (Online) | Submit via www.hometax.go.kr or Son-taek mobile app using digital certificate / joint certificate. | Requires a Korean digital ID (Joint Certificate / Financial Certificate) and Korean language comprehension. |
| Local District Tax Office | Visit the competent district tax office (세무서) having jurisdiction over your residential domicile in person. | Long waiting times in May; English language assistance may be limited depending on the local branch. |
3. Required Documents & How to Claim Your Tax Refund
To ensure all deductible expenses and personal credits are properly applied, prepare the following documents before May:
- Withholding Tax Receipts (원천징수영수증): Issued by your Korean payers for employment (근로소득), freelance business (사업소득 3.3%), or other income (기타소득).
- Alien Registration Card (ARC / 외국인등록증): Copy of front and back showing valid foreigner registration number.
- Bank Account Information: A Korean commercial bank account under your exact ARC name for direct deposit of tax refunds.
- Proof of Dependents (If applicable): Apostilled family relationship certificates proving basic deduction eligibility for spouse or children.
If the tax withheld during 2025 exceeds your final calculated tax liability, you are entitled to a refund. Once your return is accepted by the tax office in May, the national tax refund is deposited directly into your designated Korean bank account in late June to early July, followed by the local income tax refund (지방소득세) in July to early August.
Frequently Asked Questions
Official NTS Foreigner Tax Guide Series
Explore all 6 chapters compiled from the 2026 National Tax Service Individual Income Tax Guide for Foreigners:
Need English Filing Support? Meet 103Tax
Lead tax accountant Kwon Ji-hyun and our bilingual tax specialists provide one-on-one English tax consultation, deduction screening, and direct electronic filing on Hometax. Whether you are an expat engineer, an E-2 instructor, or a freelance contractor under 3.3% withholding, we ensure full statutory compliance and maximize your legal tax refund.