Thailand Corporate Tax Deadlines 2027: Full Filing Calendar

Thailand corporate tax deadlines barely change from one year to the next, but 2027 has one change that matters: the extra eight days for filing online are only confirmed until 31 January 2027. Below is every 2027 filing date for a company with a 31 December year-end. You will also find the dates to plan for if that grace period is not renewed, and a simple routine that keeps a company from filing late.

Thailand Corporate Tax Deadlines 2027 at a Glance

Every company registered in Thailand, Thai-owned or foreign-owned, works to the same dates. Four filings repeat every month. The rest come once a year.

The VAT deadline comes from the Revenue Department's VAT rules, and the PND.50 and PND.51 deadlines from its corporate income tax rules. When a deadline falls on a weekend or public holiday, it moves to the next working day.

The Eight-Day E-Filing Grace Period Is Only Confirmed Until January 2027

For years, companies that file online have had eight extra days for most Revenue Department returns. That is why so many people think of the 15th as the withholding tax deadline and the 23rd as the VAT deadline. Legally, they are not. The extra days come from a Ministry of Finance notification that is renewed three years at a time. The current one covers online filings made up to 31 January 2027, as Tilleke & Gibbins and Nishimura & Asahi reported when it was last renewed. The round before that ran from February 2021 to January 2024, according to Forvis Mazars.

It has been renewed every time it was about to run out, so another renewal is likely. But as of 12 November 2026 no new notification has been published, and nobody can promise one.

Our advice: from February 2027, plan every return for the legal deadline: the 7th for withholding tax and PP.36, the 15th for VAT. If the grace period is renewed, you have eight days of slack. If it is not, you are still on time. We will update this page as soon as an announcement is made.

Month-by-Month Calendar for 2027 Monthly Filings

Each row is one month of transactions and the dates its returns are due. Weekends and the confirmed public holidays have already been taken into account.

Three things to watch:

• Songkran runs from Tuesday 13 to Thursday 15 April 2027. The March VAT return and social security payment therefore move to Friday 16 April. Most offices are quiet that whole week, so file before the holiday starts.

• Chulalongkorn Day, 23 October 2027, is a Saturday. The substitute holiday is expected on Monday 25 October, which is why the online VAT date for September is shown as Tuesday 26 October. Treat it as provisional.

• The Cabinet has not yet approved the full 2027 holiday list. If a new holiday or substitute day lands on one of these dates, the deadline moves again. Filing two or three working days early removes the risk completely.

A VAT-registered company files PP.30 every month, including months with no sales at all. Social security contributions are worked out on wages of up to THB 17,500 a month from 2026 to 2028. That means the most an employer pays is THB 875 per employee a month, and the employee pays the same (DLA Piper).

Annual Deadlines in 2027 for December Year-End Companies

These dates apply to a company whose financial year ends on 31 December. If your year ends on another date, the same rules count from your own year-end.

The AGM, the shareholder list and the financial statements depend on each other. The meeting cannot approve accounts that have not been audited, and the DBD filing cannot happen before the meeting. So one late audit can push three deadlines at once. The fines add up too. Holding the AGM late can cost the company up to THB 20,000 and its directors up to THB 50,000. Filing the financial statements late can lead to fines of up to THB 100,000, charged to both the company and its directors and rising with each month of delay (Forvis Mazars). These are maximums. The DBD often settles short delays for less, but there is no reason to test it. Our guide to the statutory audit in Thailand explains how to keep the audit on schedule.

Why the Half-Year Return (PND.51) Deserves Extra Care

PND.51 is the deadline that costs companies the most money. By the end of August you have to estimate the profit for the whole year and pay half the tax on that estimate. If the estimate turns out more than 25% below the real profit, and you cannot show a good reason, the company pays a surcharge of 20% of the tax shortfall (Forvis Mazars).

The safe way to estimate is with real numbers. Close the books for January to June properly, look at the orders and contracts already in hand for the second half, and write down how you reached the figure. If the year then goes differently, that note is your explanation to the Revenue Department.

How to Make Sure You Never Miss a Deadline

A missed deadline is almost never about tax knowledge. It is a busy week, an invoice that arrived late or a holiday nobody planned for. Five habits fix that:

1. Treat the legal deadline as your deadline. Aim for the 7th and the 15th. Grace days are a safety net, not a plan.

2. Close the books by the 5th of each month. Withholding tax depends on knowing every payment you made last month, so ask suppliers for tax invoices and receipts when you pay them, not at month-end.

3. Put the year's dates into one shared calendar in January. Include the Songkran week and the long weekends, and set each reminder five working days before the due date.

4. Book your auditor before the year ends. Auditors are busiest from February to April. Agreeing the fieldwork dates in December protects the 30 April AGM, and with it the DBD and PND.50 dates.

5. Do a PND.51 check in July. Compare the actual profit for January to June with your full-year plan, so the August estimate is a decision rather than a guess.

Monthly bookkeeping makes all five easier. Our guide to bookkeeping in Thailand explains what a good monthly routine looks like.

What to Do If You Have Already Missed a Deadline

File as soon as you can. Late tax carries a surcharge of 1.5% of the tax due for each month or part of a month (Revenue Code, Section 27). One day late counts as a full month, so waiting until the end of the month saves nothing.

Then find out why it happened and fix that: a missing invoice, a holiday, a staff change. One late return is a cost. A pattern of late returns is one of the things that draws the Revenue Department's attention, as we explain in five red flags that lead to a tax audit in Thailand.

Frequently Asked Questions

What are the main Thailand corporate tax deadlines in 2027?

Every month: withholding tax and PP.36 by the 7th, VAT (PP.30) and social security by the 15th. For a 31 December year-end: PND.50 for 2026 by 31 May 2027, audited financial statements to the DBD within one month of the AGM, and the 2027 PND.51 by 31 August 2027.

Is the eight-day e-filing extension still available in 2027?

It is confirmed for online filings made up to 31 January 2027. It has been renewed in three-year rounds before, but no new renewal had been published by 12 November 2026. Plan for the legal deadlines from February 2027 until it is confirmed.

When is PND.50 due in 2027?

For a company with a 31 December 2026 year-end, 150 days after year-end is Sunday 30 May 2027, so the return and payment are due on Monday 31 May 2027. If the e-filing extension is renewed, online filers have until Monday 7 June 2027.

When is PND.51 due in 2027?

For a 31 December year-end, the 2027 half-year return is due on Tuesday 31 August 2027, or Wednesday 8 September 2027 for online filing if the extension is renewed.

Do I need to file VAT in a month with no sales?

Yes. A VAT-registered company files PP.30 every month, even when there were no sales or purchases.

What happens if a deadline falls on a public holiday?

It moves to the next working day. The 2027 holiday list has not been approved by the Cabinet yet, so file a few working days early rather than counting on a holiday shift.

These dates come from the Revenue Department, Department of Business Development and Social Security Office rules linked above, applied to the 2027 calendar by our accounting team, who file these returns for clients every month. If you are just setting up a company, most of these obligations start from your first month, so read this alongside our guide to registering a company in Thailand as a foreigner. And if you would rather not keep track of a dozen dates across three government offices, our accounting services team can file them for you.

General information, not tax advice. Dates checked on 12 November 2026. Confirm the exact date with our team or the Revenue Department before you file.