Thailand Tax Filing Deadlines 2026: Every Monthly and Annual Filing for Companies

Settlr GlobalSep 15, 20266 min read

Running a company in Thailand means keeping several compliance clocks moving at once. Withholding tax, VAT and Social Security are due every month, while corporate income tax, audited financial statements and Department of Business Development (DBD) filings follow their own half-year and annual deadlines.

The table below lists the 2026 deadlines for a Thai limited company with a 1 January to 31 December accounting year. Where filing on paper and filing online have different deadlines, both are shown. Companies with a different accounting year should count PND.51, PND.50, the AGM and the DBD filings from their own year-end. If you would rather hand these filings over, see our accounting and tax services.

Thailand tax filing deadlines 2026 for companies

PND.1 (withholding tax on employee salaries): online by the 15th of the following month, which has been mandatory since the January 2024 tax month. Paper is accepted only with a letter explaining why you can't file online, by the 7th of the following month.
PND.3 / PND.53 (withholding tax on payments to individuals / to companies): paper by the 7th of the following month, online by the 15th.
PND.54 (withholding tax on payments to foreign companies): paper by the 7th of the following month, online by the 15th.
PP.30 (monthly VAT return, VAT-registered companies): paper by the 15th of the following month, online by the Revenue Department's online date, normally the 23rd and moved when it falls on a holiday (26 October in October 2026).
SSO Form 1-10 (employer and employee Social Security contributions): by the 15th of the following month, or 7 working days after the 15th when you file through SSO e-Service and pay by e-Payment.
PND.51 (half-year corporate income tax): paper by 31 August 2026, online by 8 September 2026.
PND.50 (annual corporate income tax return, year ended 31 December 2025): paper by 2 June 2026 (moved from 30 May, a holiday), online by 8 June 2026.
AGM (shareholders approve the audited financial statements): within 4 months of year-end, so by 30 April for a 31 December year-end.
Financial statements to DBD: within 1 month of the AGM approval, on paper or through DBD e-Filing.
BOJ.5 (shareholder list filed with DBD): within 14 days of the AGM, on paper or through DBD e-Filing.

When a deadline falls on an official holiday, it moves to the next working day. In 2026, for example, the Revenue Department moved the 15 August paper deadline for PP.30 to 17 August. For every month's exact dates, see our Thailand tax calendar 2026.

Individuals file separately from the company: PND.90 or PND.91 is due between January and March of the following year, and for tax year 2025 the Revenue Department set 31 March 2026 for paper returns and 8 April 2026 for online returns (see our guide to 2026 personal income tax brackets and withholding).

Key takeaways

Thai companies file PND.1, PND.3/53, PND.54, PP.30 and Social Security every month, each with its own deadline.
For a calendar-year company, PND.51 is due on 31 August 2026 on paper or 8 September 2026 online, and the 2026 PND.50 deadline was 2 June on paper or 8 June online.
Shareholders must approve the audited financial statements within four months of year-end. The statements go to DBD within one month of that approval, and the BOJ.5 shareholder list within 14 days of the AGM.

Monthly tax filing deadlines: PND.1, PP.30 and SSO

The easiest way to manage the Thailand tax calendar 2026 is to treat compliance as a repeating monthly cycle.

PND.1: salary withholding tax

PND.1 reports personal income tax withheld from employee salaries. The Revenue Department requires employers to file PND.1, PND.1 Kor and PND.1 Kor Special electronically, starting with income paid in January 2024. An employer that can't file online must file on paper with a letter explaining why.

This filing should be connected directly to payroll. Once salaries are calculated, your accounting or payroll team should determine the withholding tax for each employee, record the liability and submit the return.

PND.3, PND.53 and PND.54

Other withholding tax forms run on the same monthly cycle. Companies paying certain fees to individuals file PND.3, payments to Thai companies go on PND.53, and certain payments to foreign companies go on PND.54. The Revenue Department's 2026 calendar shows all three due by the 7th of the following month on paper, or the 15th online.

PP.30: monthly VAT

VAT-registered businesses file PP.30 every tax month. The Revenue Code requires the monthly return within the first 15 days of the following month, and the Revenue Department's 2026 calendar sets the online deadline on the 23rd. When the 23rd falls on a holiday the online date moves: in October 2026 it is 26 October.

VAT should not be treated as a year-end exercise. Input VAT documents, output VAT invoices and supporting records should be reconciled every month.

Social Security

Employers run a separate Social Security cycle. The Social Security Office requires employers to submit Form SSO 1-10 and pay contributions by the 15th of the month after the payroll month. Under a Ministry of Labour notice, employers who file through SSO e-Service and pay by e-Payment get 7 more working days after the 15th. The extension is set for a fixed period, so check the current notice on sso.go.th.

Because Revenue Department and Social Security filings run through different systems, completing payroll doesn't automatically complete every government filing.

Half-year PND.51

PND.51 is the half-year corporate income tax filing.

Under the Revenue Code, companies generally estimate annual net profit and pay half of the estimated annual corporate income tax within two months after the end of the first six months of the accounting period. The amount paid is credited against the final annual corporate income tax liability.

For a company with a 1 January to 31 December accounting year, the Revenue Department's 2026 calendar gives:

31 August 2026 for paper filing.
8 September 2026 for online filing.

PND.51 deserves more attention than many founders give it. Your accountant needs current bookkeeping to make a reasonable estimate of the year's result, and waiting until August to reconcile six months of transactions makes that much harder.

Annual PND.50 and financial statements

PND.50 is the final annual corporate income tax return. Companies file it, with their audited accounts, within 150 days after the end of the accounting period.

For accounting periods that ended on 31 December 2025, the 150-day deadline fell on 30 May 2026, an official holiday, so the Revenue Department's calendar moved the paper deadline to 2 June 2026. The online deadline was 8 June 2026.

This is why companies shouldn't copy last year's dates into a spreadsheet: weekends and official holidays change the actual filing date.

PND.50 should also reconcile with your audited accounts, withholding tax credits and the PND.51 payment already made during the year.

Personal tax filing deadline: PND.90 and PND.91

For tax year 2025, the Revenue Department set 31 March 2026 for paper returns and 8 April 2026 for online returns. Returns for tax year 2026 are filed between January and March 2027; the Revenue Department announces the exact online date each year.

PND.94, the half-year personal return for January to June income under sections 40(5) to 40(8), is filed between July and September on paper, and online by 8 October 2026.

E-filing extensions and holiday moves

Online deadlines run later than paper ones: 15th instead of 7th for withholding tax, and the Revenue Department's online date, normally the 23rd, instead of the 15th for PP.30.

When a deadline falls on an official holiday it moves. In 2026 the PND.50 paper deadline moved from 30 May to 2 June, and the October PP.30 online deadline moved from 23 October to 26 October.

If the Revenue Department's e-filing system fails, you can file and pay within 7 working days after the online deadline, together with an extension request at your area Revenue office (see the Revenue Department e-Filing extension page).

For Social Security, a Ministry of Labour notice gives employers who file through SSO e-Service and pay by e-Payment 7 more working days after the 15th. The extension is set for a fixed period, so check the current notice on sso.go.th.

Do not forget the DBD filings

Tax filing and financial statement filing are separate obligations.

For Thai limited companies, audited financial statements must be presented for shareholder approval within four months after the end of the accounting year. The company then submits the financial statements to DBD within one month of the shareholder meeting that approved them, on paper or through DBD e-Filing. It must also send DBD a copy of its shareholder list (form BOJ.5) within 14 days of the annual general meeting.

For a company with a 31 December year-end, this normally means holding the AGM no later than the end of April and preparing the DBD filings straight afterwards.

Audit requirement: all Thai limited companies

A common misunderstanding among small businesses is that an audit is only required once the company becomes large. That is not the rule for a Thai limited company.

Under the Accounting Act, a company's financial statements must be audited, with an opinion from an authorised auditor. Only Thai registered partnerships below the ministerial thresholds are exempt. The audited statements are then submitted to shareholders for approval.

Even a small Thai limited company should plan its year-end audit well before the filing deadline. The practical sequence is:

Close bookkeeping → reconcile tax accounts → prepare financial statements → auditor review → shareholder approval → DBD filings → complete the annual tax return.

Leaving bookkeeping unfinished until the audit starts usually creates unnecessary pressure around the annual deadlines. Businesses that prefer to outsource this cycle can use Settlr Global's accounting and tax services for monthly bookkeeping, tax filings and year-end compliance.

Penalty table

Missing a deadline can create several different costs. A late-filing fine and a surcharge on unpaid tax can apply separately.

PND.50 return and accounts not filed on time: fine of up to THB 4,000 (Revenue Code section 35).
PND.51 not filed on time: fine of up to THB 2,000, plus a 20% surcharge on the tax due.
Corporate income tax paid late: 1.5% surcharge per month or part of a month.
PND.51 profit underestimated by more than 25% without reasonable cause: 20% surcharge on the tax underpaid.
VAT paid late: 1.5% surcharge per month or part of a month on the unpaid VAT (section 89/1).
PP.30 not filed on time: penalty of twice the tax due (section 89), which can be reduced under Revenue Department rules.
Social Security contribution paid late: 2% additional charge per month, from the 16th of the month it was due.
Financial statements not filed with DBD on time: civil fine of up to THB 50,000 (Accounting Act section 30); a director or manager responsible can be fined as well (section 40).
BOJ.5 not filed within 14 days of the AGM: civil fine of up to THB 10,000.

The exact penalty depends on the type of violation and the circumstances, so correct late filings promptly rather than leaving them until the next reporting period.

Calendar download

The simplest compliance system is one where deadlines appear automatically before they become urgent.

Instead of keeping separate reminders for PND.1, PND.3/53, PND.54, PP.30, Social Security, PND.51, PND.50, the AGM and the DBD filings, put them in one operating calendar.

For companies with a non-calendar financial year, adjust your PND.50, PND.51, audit and DBD dates to your actual accounting period.

Download the ICS calendar and add the main Thailand accounting deadlines directly to your business calendar so your finance team has reminders before each filing date.

FAQs

What are the monthly tax filing deadlines in Thailand for 2026?

Withholding tax returns (PND.1, PND.3, PND.53 and PND.54) are due by the 7th of the following month on paper or the 15th online, and PND.1 must be filed online unless you attach a letter explaining why you can't. PP.30 VAT is due by the 15th on paper or the 23rd online. Social Security contributions are due by the 15th. Under a Ministry of Labour notice, employers who file through SSO e-Service and pay by e-Payment get 7 more working days after the 15th. The extension is set for a fixed period, so check the current notice on sso.go.th.

When is PND.51 due in 2026?

For companies with a January to December accounting year, PND.51 is due on 31 August 2026 on paper or 8 September 2026 online.

When is PND.50 due in 2026?

PND.50 is due within 150 days after the accounting year ends. For years that ended on 31 December 2025, the paper deadline moved to 2 June 2026 because 30 May was an official holiday, and the online deadline was 8 June 2026.

Does every Thai limited company need an annual audit?

Yes. The Accounting Act requires a Thai limited company's financial statements to be audited by an authorised auditor before they are presented to shareholders for approval.

When do financial statements need to be filed with the DBD?

Shareholders must approve the audited statements within four months after year-end, and the company must submit them to DBD within one month of that approval. The BOJ.5 shareholder list is due within 14 days of the AGM.

How can a company avoid missing Thailand tax deadlines?

Keep bookkeeping current every month rather than rebuilding the accounts before PND.51 or PND.50. Assign an owner for payroll, VAT, withholding tax, SSO and the annual filings, and keep every deadline in one shared calendar.

What is the tax filing deadline in Thailand?

Companies file withholding tax by the 7th of the following month on paper or the 15th online, and PP.30 VAT by the 15th on paper or the Revenue Department's online date, normally the 23rd. Individuals file PND.90 or PND.91 between January and March; for tax year 2025 the deadlines were 31 March 2026 on paper and 8 April 2026 online.

Can I get an extension if e-filing fails?

If the Revenue Department's system fails on the deadline, you can file and pay within 7 working days after the online deadline by submitting an extension request with supporting documents at your area Revenue office.

Never miss another filing deadline. Download the ICS calendar and put Thailand's key tax, accounting and compliance dates directly into your calendar.