What expats in Thailand should clarify for personal income tax filing in 2026

Foreign entrepreneurs living in Thailand are getting ready for the annual tax filing, as the deadline for filing for annual personal income tax is approaching. All filings should be submitted by March 31, however, the online filings can be done via the Thai Revenue Department by April 8.

An expatriate is obligated to submit tax reports if he or she has established full tax residency. Under Thai rules, if you are present in the country for 183 days or more during a calendar year, you are generally considered a tax resident. You are also required to check whether additional income transferred from another country may fall within the scope of Thai taxation. Those who have not established residency are usually taxed only on income that comes from Thai sources.

According to the recent confirmation by the Thai Revenue Department, foreign income earned from Jan. 1, 2024 and onward may be taxable when it is brought into the country by its legal tax residents. For this reason, foreign entrepreneurs are advised to review how their cross-border transfers affect their tax position if their salary payments, investment income or rental earnings come from overseas.

In Thailand, source-based and residence-based taxation principles are applied. If a person working directly in Thailand receives any form of income, it generally becomes taxable even if the salary was not paid to the local bank. This may affect professionals working for businesses from other countries while they are in Thailand.

It is important to file a personal income return when annual income exceeds the relatively low established thresholds. Therefore, many foreign workers may need to submit a return even if their employer has already withheld it throughout the year. Single taxpayers are required to pay THB 120,000, and married taxpayers are required to pay THB 220,000.

The rates for the personal income tax system range from 0% to 35%, depending on income level. Here is the full breakdown:

• For taxable income up to THB 150,000 (US$4,170), the tax rate is 0%
• THB 150,001 – THB 300,000 (US$4,170 – US$8,335), the tax rate is 5% 
• THB 300,001 – THB 500,000 (US$8,335 – US$13,890), the tax rate is 10% 
• THB 500,001 – THB 750,000 (US$13,890 – US$20,835), the tax rate is 15% 
• THB 750,001 – THB 1,000,000 (US$20,835 – US$27,780), the tax rate is 20% 
• THB 1,000,001 – THB 2,000,000 (US$27,780 – US$55,560), the tax rate is 25% 
• THB 2,000,001 – THB 5,000,000 (US$55,560 – US$138,890), the tax rate is 30% 
• Above THB 5,000,000 (US$138,890), the tax rate is 35%

Expatriates are eligible for common allowances, such as a personal allowance of THB 60,000, a spouse’s allowance of THB 60,000 if the spouse doesn’t earn an independent income, and THB 30,000 per child. Employment income also benefits from an expense deduction of up to THB 100,000. These deductions lower the taxable income before applying progressive tax rates.

Those earning only employment income must submit the Por Ngor Dor 91 form, while those with additional income sources such as consulting fees, rental income, or investment returns must submit the Por Ngor Dor 90 form.

According to tax professionals in the country, expatriates mainly struggle with understanding how foreign income transfers interact with local tax laws. Any funds transferred from overseas without proper documentation of the income’s origin or the year it was earned may cause reporting issues, and there could be complications with claiming deductions.