Thailand Tax Calendar 2026: Every Deadline Your Company Cannot Afford to Miss
Running a business in Thailand means filing something with a government department almost every month. VAT returns, withholding tax, payroll tax, corporate income tax estimates, annual returns, and financial statement submissions — each with its own deadline and its own penalties for getting it wrong.
Most foreign business owners discover a missed deadline the hard way: when the fine arrives. This Thailand tax calendar for 2026 puts every obligation in one place so that does not happen to you.
2026 Thailand Tax Calendar at a Glance
| Deadline | Filing | What It Covers | Filed With |
|---|---|---|---|
| 15th of every month | PP.30 | Monthly VAT return (even if nil revenue) | Revenue Department |
| 15th of every month | PND 1 | Payroll withholding tax | Revenue Department |
| 15th of every month | PND 3 / PND 53 | Withholding tax on service payments | Revenue Department |
| 15th of every month | Social Security | Employer and employee contributions | Social Security Office |
| End of February / early March (e-filing) | PND 1a | Annual payroll withholding summary | Revenue Department |
| 31 March (paper) / 8 April (e-filing) | PND 90 / PND 91 | Personal income tax return | Revenue Department |
| 30 May | PND 50 | Annual corporate income tax return | Revenue Department |
| Within 1 month of shareholder approval | DBD Annual Filing | Audited financial statements | Dept of Business Development |
| 31 August | PND 51 | Mid-year corporate income tax estimate | Revenue Department |
Dates assume a December year-end. E-filing deadlines for monthly returns are typically extended to the 23rd. If a deadline falls on a weekend or public holiday, it moves to the next working day.
Monthly Tax Filing Deadlines for Thai Companies
Four filings recur on the 15th of every month throughout the year. These are the backbone of your company's tax compliance, and missing even one triggers automatic penalties.
PP.30 — VAT Return
If your company is VAT registered, a PP.30 return must be filed by the 15th of the month following the tax period. This applies even if your company had zero revenue that month. A nil return is still a required return. Late filing carries a minimum penalty of 500 THB per return (which may be higher depending on the assessment) plus a 1.5% monthly surcharge on any unpaid VAT.
PND 1 — Payroll Withholding Tax
If your company has employees, you must withhold personal income tax from their salaries and remit it to the Revenue Department by the 15th of the following month. This applies from the first month you have a Thai employee on payroll — including yourself as a salaried director.
PND 3 / PND 53 — Service Withholding Tax
When your company pays for services — an accountant, a consultant, a freelancer, a landlord — you are required to withhold tax at source and file a return by the 15th of the following month. PND 3 covers payments to individuals; PND 53 covers payments to companies. The withholding tax rates range from 1% to 5% depending on the type of payment.
If the 15th falls on a weekend or public holiday, the deadline moves to the next working day. Thailand has a significant number of public holidays — check the calendar each month rather than assuming.
Social Security Contributions
If your company has employees, social security contributions must be remitted to the Social Security Office by the 15th of the following month. Both employer and employee contribute 5% of salary (currently capped at 875 THB each per month). Note that social security is submitted to the Social Security Office — not the Revenue Department.
For e-filing via the Revenue Department's online system, monthly tax deadlines are typically extended to the 23rd of the month. Confirm each filing type as extensions may vary.
Thailand Tax Calendar 2026: Annual and Semi-Annual Deadlines
Beyond the monthly cycle, your company faces several critical annual and semi-annual filings. These carry larger penalties and have more complex preparation requirements.
End of February (paper) / early March (e-filing) — PND 1a (Annual Payroll Summary)
An annual summary of all personal income tax withheld from employee salaries during the previous year. Filed with the Revenue Department.
31 March — Personal Income Tax (Paper Filing)
If you as a director or business owner need to file personal income tax (PND 90 or PND 91), the paper filing deadline is 31 March. The personal income tax return covers all assessable income for the previous calendar year. Use our Personal Income Tax Calculator to estimate your liability before you file.
8 April — Personal Income Tax (E-Filing)
The Revenue Department extends the deadline by eight days for returns filed electronically through rd.go.th. Most filers now use this option.
30 May — PND 50 (Annual Corporate Income Tax)
Your company's annual corporate income tax return, due within 150 days of the end of your accounting period. For companies with a December year-end, that means 31 May. This filing requires audited financial statements prepared by a licensed CPA — your end-of-year audit must be completed before PND 50 can be filed. Read our full guide on how to file PND 50 for the complete process.
Within 1 month after shareholder approval of accounts — DBD Annual Filing
Separately from PND 50, your audited financial statements must also be filed with the Department of Business Development (DBD). This is a different government department with its own submission process. Many companies miss this because they assume the Revenue Department filing covers it — it does not.
31 August — PND 51 (Mid-Year CIT Estimate)
A mid-year estimate of your company's corporate income tax for the first six months of the accounting period. If your estimate falls short of actual net profit by more than 25%, the Revenue Department applies a 20% surcharge on the tax shortfall when PND 50 is filed. Getting a reasonable estimate matters — speak to your accountant in July to prepare this properly.
The Real Cost of Missing a Deadline
Thai tax penalties are automatic — no formal notice is required before they apply:
- Late PP.30: minimum 500 THB per return (may be higher depending on assessment) + 1.5% per month on unpaid VAT
- Late PND 1/3/53: 1.5% per month surcharge on unpaid withholding tax
- Late PND 50: 1.5% per month surcharge + fixed late filing penalty (typically up to 2,000 THB)
- PND 51 underestimate (>25% off): 20% surcharge on the tax shortfall
- Late DBD filing: fines and potential impact on company good standing
Penalties stack. A company that misses several consecutive monthly filings can accumulate more in penalties than the original tax owed. The cost of staying compliant is almost always less than the cost of catching up.
How to Stay on Top of Your Thailand Tax Calendar
A few practical steps that make a real difference: set recurring calendar reminders for the 10th of every month — five days before the filing deadline gives you enough buffer to catch issues. At the start of each year, ask your accountant for a written schedule of every filing they handle and every deadline you need to be aware of. Keep a separate reminder for annual filings — PND 50, PND 51, and DBD — because these require preparation weeks in advance, not on the day.
The most reliable approach is working with an accounting firm that manages the full calendar on your behalf. At Attori Law, our team handles monthly VAT, withholding tax, and payroll filings, coordinates your annual audit, and ensures PND 50 and DBD filings are submitted on time.
Learn about our bookkeeping and accounting packages or get in touch to discuss what your business needs.
Frequently Asked Questions: Thailand Tax Calendar 2026
What happens if the 15th falls on a public holiday?
If the filing deadline falls on a public holiday or weekend, it moves to the next working day. Thailand has a significant number of public holidays — it is worth checking the calendar each month rather than assuming.
Do I need to file monthly returns if my company has no activity?
Yes. If your company is VAT-registered, PP.30 must be filed every month regardless of revenue. If you have employees, PND 1 must be filed. If you made qualifying payments to service providers, PND 3/53 applies. Nil returns are still required returns.
Our company was only registered mid-year. Do we still need to file PND 51?
PND 51 covers the first six months of your accounting year. If your company was registered after your accounting year began, you may need to file a short-period return. The specific requirement depends on your registration date and fiscal year — confirm this with your accountant.
Can I file all these returns myself?
Monthly filings (PP.30, PND 1/3/53) can technically be filed via the Revenue Department's online portal. In practice, most foreign business owners with more than a handful of transactions use an accounting firm. The time cost and error risk of self-filing typically exceeds the cost of a monthly accounting package.
What is the DBD filing and is it the same as the Revenue Department filing?
No — they are entirely separate. The Revenue Department (rd.go.th) handles tax filings. The Department of Business Development (DBD) handles the annual corporate filing of financial statements. Both must be completed and both have consequences for non-compliance.
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