For businesses operating in Korea, staying compliant with corporate tax (CIT) and withholding tax (WHT) deadlines is crucial to avoiding penalties. Below is a comprehensive guide to help businesses navigate the key tax deadlines for 2025.
1. Corporate Income Tax (CIT) Deadlines
Corporations in Korea are required to file and pay corporate tax based on their fiscal year-end. Most companies follow a December 31 fiscal year-end, but different fiscal years apply to some businesses.
Key CIT Deadlines for 2025
| Tax Obligation | Deadline (2025) | Details |
|---|---|---|
| Preliminary Corporate Tax Payment (중간예납) | August 31, 2025 | Companies must pay half of their previous year’s tax liability as an advance payment. |
| Annual CIT Return (법인세 확정신고) | March 31, 2025 | Final corporate tax return filing and payment for companies with a December 31 fiscal year-end. |
| Annual CIT Return (for non-December fiscal year) | 3 months after fiscal year-end | Companies with a different fiscal year-end must file within 3 months after the year-end. |
| Corporate Local Tax (지방소득세 법인세분) | April 30, 2025 | Corporate local tax return must be filed one month after the CIT deadline. |
Key Notes on Corporate Tax Compliance
- Electronic filing (Hometax): All CIT filings must be submitted via the National Tax Service (NTS) Hometax system.
- Penalty for Late Filing: Late corporate tax payments may be subject to interest penalties.
2. Withholding Tax (WHT) Deadlines
Employers and businesses making payments subject to withholding tax (e.g., salary, interest, dividends, service fees) must file and remit taxes by the following deadlines:
Key WHT Deadlines for 2025
| Tax Obligation | Deadline (2025) | Details |
|---|---|---|
| Monthly Withholding Tax (원천세 신고) | 10th of the following month | Employers must withhold and remit tax on salaries, service payments, and interest/dividends. |
| Bi-Annual Withholding Tax Filing (반기별 원천세 신고) | July 10, 2025 & January 12, 2026 | Companies eligible for bi-annual withholding tax filing must report tax withholdings twice a year. |
| Year-End Tax Settlement (연말정산) | March 11, 2025 | Employers must complete the year-end tax settlement process for employees. |
| Local Income Tax (지방소득세 특별징수) | 10th of the following month | A separate local income tax filing is required for salaries and service income. |
Key Notes on Withholding Tax Compliance
- Who Must File?
- Businesses making salary payments to employees.
- Companies paying foreign service providers (subject to Korean WHT rates).
- Penalties for Late Payments
- Late filing of withholding tax can result in a 10-20% penalty plus interest charges.
3. How to Stay Compliant with Korean Tax Deadlines?
To avoid late filing and penalties, companies should:
✅ Use Hometax for electronic filing (https://www.hometax.go.kr)
✅ Set up automated reminders for key tax deadlines
✅ Consult a Korean tax professional to review tax compliance requirements
Staying compliant with Korean corporate and withholding tax deadlines is essential for smooth business operations. If you have any questions or need assistance with tax filings, feel free to contact a Korean Tax Expert.
