Thai Company Monthly Compliance Calendar: Every Deadline

Running a company in Thailand means dealing with a recurring set of government filings throughout the year. If you are new to this, it can feel overwhelming at first. Different deadlines apply to different taxes, different agencies are involved, and the penalties for missing a submission add up quickly. This guide breaks the Thai company compliance calendar down into plain language so you know exactly what is due, when it is due, and why it matters.

Understanding the Two Main Tax Authorities

Before looking at specific deadlines, it helps to know who you are filing with. Most monthly compliance obligations in Thailand sit with the Revenue Department, which oversees corporate income tax, value added tax, and withholding tax. The Social Security Office is the other key agency, handling monthly contributions for any employees on your payroll. A smaller number of companies also deal with the Excise Department if they operate in specific industries such as alcohol, tobacco, or certain services, but for most small and foreign-owned businesses, the Revenue Department and the Social Security Office cover the bulk of monthly obligations.

VAT Returns: The 15th or 23rd of Every Month

If your company is registered for VAT, which is required once your annual revenue reaches 1.8 million baht, you must file a VAT return every single month without exception, even if you had zero sales that month. The standard paper filing deadline falls on the 15th of the following month. For example, your January VAT return is due by 15 February. If you file through the Revenue Department's online portal, which most businesses now do, the deadline is extended to the 23rd of the following month. The form used is PP.30, and it reports your output tax collected from customers against your input tax paid to suppliers. If your output tax exceeds your input tax, you pay the difference to the Revenue Department. If it goes the other way, you accumulate a credit. Missing this deadline triggers a surcharge of 1.5 percent per month on any tax owed, plus a fine, so this is one to treat seriously every single month.

Withholding Tax: Also Due on the 7th, 15th, or 23rd

Withholding tax is a separate monthly obligation. Whenever your company pays certain types of income to individuals or other companies, Thai law requires you to deduct a percentage at source and remit it to the Revenue Department. Common examples include salary payments to employees, payments to freelancers or service providers, and rental payments for office space. Salaries are reported on form PND.1, while payments to companies and other service providers use PND.3 or PND.53 depending on whether the recipient is an individual or a juristic person. The standard paper deadline is the 7th of the following month, while online filers get until the 15th. It is worth noting that if you have employees, withholding tax on salaries must be filed even in months when no salaries were actually paid, if the company has standing employees on record.

Social Security Contributions: Due by the 15th

Any company with employees must register with the Social Security Office and make monthly contributions on behalf of those employees. Both the employer and the employee contribute a percentage of the employee's salary, subject to a monthly wage cap that the Social Security Office sets and periodically reviews. The employer deducts the employee's share from their salary and combines it with the company's own contribution, then submits the total to the Social Security Office by the 15th of the following month. Filing is done through the SSO's online system in most cases. Employees covered by social security are entitled to benefits including healthcare, maternity pay, and unemployment support, so keeping this filing current is both a legal and a practical obligation if you want to retain staff.

Mid-Year and Annual Corporate Income Tax

Corporate income tax works on a slightly different cycle from the purely monthly filings. Thai companies pay corporate income tax in two installments. The first, known as the half-year tax return filed on form PND.51, is due within two months of the end of your first six-month accounting period. For most companies whose fiscal year runs January to December, this means the PND.51 is due by the end of August. The second is the annual tax return, form PND.50, which must be filed within five months of your fiscal year end, so by the end of May for a December year-end. While these are not monthly filings, they belong in your compliance calendar because the half-year estimate requires you to forecast your annual profit reasonably accurately. Getting it significantly wrong can attract penalties.

Specific Industry and Occasional Filings to Know About

Beyond the regular monthly cycle, certain businesses have additional obligations. Companies in the hospitality, entertainment, or certain service sectors may need to file specific reports with local authorities or the Excise Department. Businesses holding a foreign business license have their own set of annual reporting conditions. If your company employs foreign staff, you must also keep work permit conditions current and report to immigration on a 90-day cycle, which sits outside the tax system but is equally important from a legal compliance standpoint. New directors, share transfers, and changes to registered capital all require filings with the Department of Business Development, and while these are event-driven rather than calendar-driven, missing them creates problems that compound over time.

How to Stay on Top of It All

The most common reason small businesses fall behind on Thai compliance is not intentional avoidance but simply losing track of which filing is due in which week. A practical approach is to maintain a simple internal calendar that marks the 7th, 15th, and 23rd of every month as compliance checkpoints, with notes on which forms apply to your business. Many foreign-owned companies outsource this entirely to an accounting firm, which handles the preparation and submission of every monthly filing and flags anything out of the ordinary. This is often more cost-effective than it appears once you factor in the time, the software, and the risk of penalties from errors. Whether you manage it in-house or work with a professional, the key is treating compliance as a monthly routine rather than a quarterly scramble.