Corporate Tax Deadlines in Thailand 2026: 14 Critical Dates Every Business Owner Must Know

Missing a tax deadline in Thailand is not simply a matter of paying a fine. It signals to the Revenue Department to scrutinize your entire business. For foreign company directors, the consequences can escalate quickly — from complications with work permit renewals to criminal liability in cases of repeated violations.

Thailand's corporate tax reporting system is demanding by design. Every month brings at least three mandatory filings. Every year adds eight key annual deadlines spread from January through August. A single accountant juggling ten clients can easily lose track. You, as a director, cannot afford to.

Below is a complete map of corporate tax obligations for a Thai limited company (Co., Ltd.) in 2026 — with specific forms, deadlines, and the relevant authorities.

Quick Answer

• Five monthly withholding tax forms are due by the 7th of each month to the Revenue Department
• VAT declaration (PP 30) is due by the 15th of each month
• Social security contributions are due by the 29th of each month
• Annual corporate income tax (PND 50) must be filed by 27 May, together with audited financial statements
• Mid-year tax declaration (PND 51) is due by 31 August
• Late filing penalties range from 1,000 to 2,000 THB per form, plus 1.5% monthly surcharge on any unpaid tax

Scenarios and Options

Scenario 1 — Company with Thai Employees and Local Suppliers

This is the most common setup for small businesses. You are required to file PND 1 (withholding from employee salaries), PND 3 (withholding from individual suppliers), and PP 30 (VAT) every month. If all your suppliers are individual Thai residents, PND 53 may not apply — but the Revenue Department still expects a nil return. Filing nothing is not the same as having nothing to declare.

Scenario 2 — Company Working with Foreign Suppliers

Once cross-border payments are involved, two additional forms enter the picture: PND 54 (withholding on payments abroad) and PP 36 (reverse-charge VAT for non-resident service providers). The standard withholding rate on foreign service payments is 15%, unless a double taxation agreement (DTA) applies. Thailand has active DTAs with over 60 countries, which can reduce this rate to 5–10% depending on income type.

Scenario 3 — Company That Owns or Leases Property

Rental income is subject to corporate income tax at 20% for profit above 3 million THB. SMEs with profit under 300,000 THB pay 0%; between 300,001 and 3,000,000 THB the rate is 15%. Rental income also triggers VAT registration if annual revenue exceeds 1.8 million THB.

Scenario 4 — Holding Structure for Investment Purposes

If a Thai company is established purely to hold assets without active operations, full reporting obligations still apply. Nil returns must be submitted on the same schedule. Annual audited accounts are mandatory for every registered company — no exceptions for size, turnover, or activity level.

Comparison Table

Monthly Obligations

Annual Obligations

Main Risks and Mistakes

1. Delegating without oversight The most costly assumption in Thai business is 'the accountant will handle it.' The company director carries personal legal responsibility for filings. If your accountant misses a deadline, the penalty is issued to the company — and the director is held accountable. Review your calendar independently.

2. Nil returns are still required Even if your company had zero transactions in a given month, you are legally required to submit nil declarations for PND 1, PND 3, PND 53, and PP 30. Failure to file a nil return is a violation — not a technicality.

3. Incorrect withholding tax rates Thailand's withholding tax system uses multiple rates depending on service type: 1% for transport, 2% for advertising, 3% for most professional services, 5% for rental payments. Applying the wrong rate triggers reassessment with surcharges.

4. Missing the AGM deadline The Annual General Meeting must be held before 30 April. Without a signed AGM resolution, auditors cannot finalize accounts. Without audited accounts, the Department of Business Development will not process filings — and work permit renewals for foreign directors can stall.

5. Skipping PND 54 on international transfers Sending money to a foreign supplier without withholding and filing PND 54 is a direct breach of the Thai Revenue Code. The Revenue Department monitors cross-border transactions through the banking system and reconciles them during audits.

6. Underestimating profit in PND 51 Many business owners overlook the August filing entirely. If your actual annual profit deviates from the estimate declared in PND 51 by more than 25%, an additional surcharge of 20% on the difference is applied. File conservatively and adjust proactively.

FAQ

What is the corporate income tax rate in Thailand in 2026? The standard rate is 20%. Qualifying SMEs — with paid-up capital under 5 million THB and annual revenue under 30 million THB — benefit from a tiered structure: 0% on profit up to 300,000 THB, 15% on profit between 300,001 and 3,000,000 THB, and 20% above that threshold.

Is an annual audit mandatory? Yes, without exception. Every registered company in Thailand must submit audited financial statements to the Department of Business Development each year, regardless of company size, turnover, or whether the business was active.

What happens if a deadline is missed? The penalty for late filing is up to 2,000 THB per form, plus a 1.5% monthly surcharge on unpaid tax. Repeated or systematic violations can result in criminal liability — fines of up to 200,000 THB and potential imprisonment under the Revenue Code.

Can filings be submitted online? Yes. The Revenue Department accepts most forms through its e-Filing portal at efiling.rd.go.th. Online submission extends each deadline by 8 calendar days — a meaningful advantage worth using consistently.

Is a full-time accountant required? The law does not require an in-house accountant, but it does require a Certified Public Accountant (CPA) for the annual audit. Monthly filings are typically handled by an outsourced accounting firm, with costs ranging from 5,000 to 25,000 THB per month depending on transaction volume.

Does a company need to register for VAT at low turnover? VAT registration becomes mandatory when annual revenue exceeds 1.8 million THB. The Thai VAT rate is 7%. Companies below the threshold may register voluntarily — useful if working with VAT-registered clients or seeking input tax credits.

What forms are needed if the company has no employees? Without staff, PND 1 and Sor Por Sor 1-10 do not apply. However, PP 30 (VAT), PND 50 (annual corporate tax), and the annual audited accounts remain fully mandatory.

How are dividends taxed in Thailand? Dividends paid to individual Thai tax residents are subject to 10% withholding tax. The same 10% rate applies to non-residents, unless a double taxation agreement provides a reduced rate.

The Thai corporate tax calendar contains 14 critical dates distributed across the full year. Missing any one of them initiates a chain reaction — penalty, surcharge, audit, and potential complications with visas and work permits. The only reliable strategy is to build a systematic reminder framework and work with an accounting team that has genuine experience managing foreign-owned businesses in Thailand.

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