Thailand Corporate Tax Deadlines for 2026
Every Thailand corporate tax deadline for 2026 in one place, from monthly VAT to the annual audit
Every company registered in Thailand, whether Thai-owned or foreign-owned, answers to the same set of Thailand corporate tax deadlines for 2026. After filing these forms for clients month after month, one pattern stands out: it's rarely the annual return that trips people up. It's the mid-year estimate. Here's the full calendar, and why that one deadline deserves more attention than it usually gets.
Thailand Corporate Tax Deadlines for 2026 at a Glance
Filing | Form | Frequency | Due (paper filing) | Due (e-filing) |
|---|---|---|---|---|
Withholding Tax | PND.1 / PND.3 / PND.53 / PND.54 | Monthly | 7th of following month | 15th of following month |
VAT | PP.30 | Monthly | 15th of following month | 23rd of following month |
Social Security | SSO contribution | Monthly | 15th of following month | - |
Half-Year CIT Prepayment | PND.51 | Mid-year | ~31 August | Short extension applies |
Annual CIT Return | PND.50 | Annual | ~150 days after fiscal year-end (~30 May) | Short extension applies |
Audited Financial Statements | DBD filing | Annual | ~5 months after fiscal year-end (~31 May) | - |
(Exact dates shift when they fall on a weekend or public holiday — confirm the specific 2026 date with the Revenue Department before filing.)
Why the Half-Year Return Deserves Extra Care
Thai corporate income tax runs on a two-part cycle. Partway through the year, every company files PND.51, a prepayment based on an estimate of full-year profit, not the actual result. Get that estimate wrong by more than 25%, and a 20% surcharge lands on the shortfall. This is genuinely the deadline that catches companies out, precisely because it asks you to forecast something that hasn't happened yet.
The second half of the cycle, PND.50, is the annual return built on your actual, audited profit, filed within 150 days of your fiscal year-end. Because it depends on audited numbers, it can't be finalized until the audit itself is done, which is exactly why the DBD deadline below sits earlier on the calendar.
The Monthly Obligations Nobody Escapes
Three filings repeat every single month, regardless of company size:
Withholding tax: the form depends on who was paid. PND.1 for employee wages, PND.3 for individual contractors, PND.53 for corporate suppliers, PND.54 for overseas service providers.
VAT (PP.30): due even in a month with zero transactions, if you're VAT-registered. Skipping a quiet month is one of the most avoidable compliance gaps we see.
Social Security contributions: due for any company with employees, filed through the SSO's own portal.
The Deadline That Quietly Controls Everything Else
Every registered company in Thailand, regardless of ownership or size, must file audited financial statements with the DBD, generally within five months of fiscal year-end. Two other dates hang off this one: the Annual General Meeting has to happen within four months of year-end, and the shareholder list (Form BOJ.5) is due 14 days after that meeting. Push the audit late, and the whole chain slips with it, including the PND.50 return that depends on it.
What a Missed Deadline Actually Costs
Most late filings carry a fixed fine plus roughly 1.5% monthly interest on any unpaid tax: real money, but rarely severe in isolation. The exception is the PND.51 underestimation penalty, at 20% of the shortfall. The bigger cost, honestly, isn't any single fine. It's that a pattern of late filings tends to draw closer Revenue Department attention over time.
Frequently Asked Questions
What are all the Thailand corporate tax deadlines for 2026?
Monthly: withholding tax, VAT, and Social Security. Annually: the PND.51 half-year prepayment (around 31 August), the PND.50 annual return (around 30 May the following year), and audited financial statements to the DBD (around 31 May).Why is the PND.51 the one people get penalized on most?
Because it's based on an estimate, not an actual result. Underestimate full-year profit by more than 25%, and a 20% surcharge applies to the gap.Does a zero-revenue month still require a VAT filing?
Yes. If you're VAT-registered, PP.30 is due monthly regardless of activity.What happens if I file late?
A fixed fine plus roughly 1.5% monthly interest on unpaid tax, or a 20% surcharge specifically for a PND.51 underestimate.
These filing rhythms come directly from the Revenue Department's own filing rules, not a generic estimate assembled from someone else's list. Our accounting team files these forms for clients every single month, which is exactly why the PND.51 estimate is the deadline we flag first here, rather than the more obvious annual return.
If you're setting up fresh, this list is worth bookmarking right after registering a company in Thailand as a foreigner, since most of these obligations start from day one. And if keeping six recurring dates straight across three government bodies isn't how you want to spend your time, talk to our Accounting Services team. It's what we do all day.
This article is a general overview, not tax advice. Confirm exact 2026 dates with our team or the Revenue Department before relying on them.