Business registration with the NTS: within 20 days.
Court registration creates the legal entity. It does not register you as a taxpayer. Those are two separate acts with two separate authorities, and the second one has a deadline attached. You must register with the district tax office within 20 days of commencing business to obtain your Business Registration Certificate (사업자등록증) and corporate tax ID.
Miss it and you face penalties, but the bigger problem is downstream. Without the BRC you cannot issue tax invoices, cannot complete the corporate bank account process cleanly, and cannot begin the D-8 sequence. It is a small deadline that blocks everything behind it.
The address problem inside that window. Your registered address has to match what you actually do. Tax offices reject applications where a business type and a premises classification don't line up: a food business at an address zoned only for offices, a training business at a co-working desk. Check the building's legal usage classification on the 등기부등본 before signing a lease, not after your registration is rejected.
This is also where your choice of structure starts to show its cost. A branch and a subsidiary carry different registration and reporting burdens from day one, which we break down in subsidiary or branch office in South Korea.
Withholding tax return and payment: by the 10th of the following month.
The day you pay your first employee, or your first non-resident contractor, or the first royalty to your parent company, you have joined a monthly cycle. Income tax withheld from salaries must be reported and remitted to the NTS by the 10th of the following month, with social insurance contributions running on their own schedules.
This is the deadline that catches companies with one employee and no local finance function. It doesn't scale with headcount. One person on payroll and fifty create the same monthly obligation.
New pressure as of late 2025: the Labour Standards Act was amended effective 23 October 2025 so that interest on delayed wage payments now applies to all employees, not only those who have left the company. Wages must be paid at least monthly on a fixed, predetermined payday, and interest accrues from the day after a missed payday. A casual approach to payday timing is now a financial liability rather than an HR inconvenience.
VAT: 25 April, 25 July, 25 October, 25 January.
Korea runs two six-month VAT taxable periods (January to June, and July to December) with preliminary returns at each quarter, which in practice means four filings a year, each due 25 days after the period closes.
There is no registration threshold. A company with modest revenue files on the same rhythm as a large one. Late filing carries a penalty on the unpaid amount plus a monthly accrual, and separate penalties attach to failures in electronic tax invoicing. Invoices must be transmitted to the NTS system, generally within a day of issuance.
For a company still finding its feet, the quarterly VAT return is usually the first moment bookkeeping quality becomes visible. Reconciling input and output VAT with incomplete records is not a task you want to discover in the last week of April.
Founders often assume "annual tax filing" is a single event. It isn't.
Add to those the year-end payroll settlement, where each employee's annual tax liability is finalised and the settlement receipt filed with the tax authorities by 10 March of the following year.
And one that is new for 2026. If you pay dividends, interest, royalties or service fees to a non-resident and apply a reduced treaty rate, the withholding agent must now file the treaty application with the tax office by the end of February of the following year. This didn't exist before. It applies to Korean-source payments made on or after 1 January 2026 regardless of when the contract was signed, and under-withholding carries a penalty of 10% of the shortfall plus daily interest. We covered this alongside the year's other rule changes in what actually changed in 2026.
The practical rule: where treaty documentation isn't complete at the moment of payment, withhold at the full statutory rate and correct afterwards. Optimism is more expensive than the cash-flow difference.
None of the above touches your visa. That runs on its own timeline, and it is the one where missed dates have personal consequences rather than financial ones.
The thing to understand about renewal is that immigration is not re-checking your original KRW 100 million. They are reading your tax filings, lease, bank activity, and shareholder register as a single continuous story. A company that registered correctly and then filed nothing for a year is not a compliant company waiting to be sorted out later. It is a dormant entity, and it renews badly. Our full breakdown of the requirements sits in the D-8 visa in Korea.
The registration process is short, ten to fourteen business days for most cases. It is also the only part of Korean market entry with a defined end.
Everything after it is recurring. The 10th of every month. The 25th of every quarter. March, April, August. February for treaty filings. Four months before your visa expires. These dates don't care that you're fundraising, hiring, or launching. They arrive anyway.
The founders who struggle in Korea are almost never the ones who found registration difficult. They're the ones who treated it as the end of the compliance work rather than the beginning of it.
Deadlines described here reflect standard cases as of August 2026 and vary by fiscal year, entity type, and turnover. Confirm your specific schedule with a qualified advisor.
If you'd rather not run this calendar yourself, we handle it. Tax registration, monthly withholding, VAT, annual filings, payroll, and visa timelines, coordinated by one team, in English. Talk to us about ongoing compliance support.