A foreigner who owes Thai income tax files a personal return once a year: form PND 91 if the only income is a salary, form PND 90 for everything else. For income earned in 2026, paper returns are due by Wednesday 31 March 2027, and online returns get a standing extension to 8 April (Revenue Department rules, checked October 2026).
Filing is the practical half of Thai tax. Whether you owe tax at all depends on your residency and on what income you bring into the country, and our page on tax residency and foreign income explains that test. This page starts where that one stops: you know you have to file, and you need the tax ID, the right form, the deadline and a way to pay.
We describe what the Revenue Department (RD) publishes. This is not tax advice. Treaties, pensions and your home country's rules change the answer from one person to the next, so use a licensed Thai accountant or tax adviser for your own return, and call the RD on 1161 when its pages are unclear.
Thai personal tax return, tax year 2026
- Salary only
- PND 91 (employment income under section 40(1))
- Any other income
- PND 90 (rent, business, foreign income brought in, or a mix)
- Paper deadline
- Wednesday 31 March 2027
- Online deadline
- 8 April 2027 expected (the standing 8-day extension; not yet announced for 2027)
- Tax ID for foreigners
- Form L.P. 10.1 at a revenue area office, within 60 days of first taxable income
- Personal allowance
- 60,000 baht
- Help line
- RD Call Center 1161
Step one: a Thai tax identification number
Thai citizens file with their 13-digit ID card number. A foreigner has no such card, so the first step is a tax identification number (TIN). The RD's English page says an individual without a Thai personal ID number must apply within 60 days of first earning assessable income, using form L.P. 10.1, at an area revenue office. Individuals may apply at any area office, not only the one where they live.
Bring your passport and something that shows the income: an employment contract, a work permit, a rental agreement or bank statements, depending on your case. The RD's English page is old (last updated in 2014) and still describes a 10-digit number, while Thai numbers now use 13 digits, so ask the office which number you will be given and write it down carefully. If you work for a Thai employer, the company's payroll or accounting staff often deal with the TIN as part of hiring; ask them before you queue. Our guide to government office hours explains lunch breaks and queue tickets.
PND 90 or PND 91: picking the right form
The RD's filing calendar separates the two annual returns by the type of income.
- PND 91 is for people whose only income is employment income (salary, wages, bonuses from an employer). Most foreigners on a work permit with a Thai employer use this one.
- PND 90 covers all types of assessable income. Use it if you have rent from a Thai condo, freelance or business income, or foreign income you brought into Thailand while resident, with or without a salary as well.
- PND 94 is a separate half-year return for some kinds of income (types 5 to 8, such as rent and business income), filed July to September. A Thai accountant can tell you whether it applies to you.
The RD's guide for foreigners living in Thailand (2024) confirms that a foreign resident reports both Thai-source income and foreign income brought in during the year on PND 90 or PND 91. A retiree whose only income is a pension brought in from abroad would therefore use PND 90, not PND 91.
Deadlines: 31 March on paper, 8 April online
Annual returns are filed between January and March for the previous calendar year. A Finance Ministry rule gives online filers eight extra days, which moves the online deadline for PND 90 and 91 to 8 April. This is a standing extension, not a special favor that has to be announced again each year.
| Income earned in | Paper return by | Online return by |
|---|---|---|
| 2025 | Tuesday 31 March 2026 | Wednesday 8 April 2026 |
| 2026 | Wednesday 31 March 2027 | Thursday 8 April 2027 (expected) |
The 2027 online date follows the same rule but had not been formally announced in October 2026. Thai government forms often show the Buddhist Era year, so "2569" means 2026; our page on Thai dates and the Buddhist Era explains the conversion.
Filing online on the RD's e-Filing site
The RD runs online filing through its e-Filing portal. You register with your tax number, then fill in the return on screen, attach evidence where asked and submit. Online returns can be paid by e-payment through Thai banks, at an ATM of the bank that issued your card, or with "Pay at Post" at a post office, according to the RD's filing page.
One practical question we could not settle from the RD's own pages: whether registration requires a Thai mobile number to receive a one-time code (OTP). Many Thai online services send codes only to local numbers, so it is sensible to have a Thai SIM in your name before you start. Our guide to Thai phone numbers explains the format and keeping a number while you are abroad. If online registration fails, file the paper form at an area revenue office before 31 March.
Paper filers lose the April week. The 8 April date applies only to returns filed online. If you plan to file on paper, or online registration is not working by mid-March, treat 31 March as your real deadline.
Allowances and rates that change the bill
Thai tax is charged on net income after expenses and allowances. Two figures from the RD's current Thai-language documents matter to most foreigners:
- The personal allowance is 60,000 baht (RD deductions sheet, January 2025).
- A tax resident aged 65 or over can treat up to 190,000 baht of income as exempt (RD list of exempt income, July 2024).
The rates have been the same since tax year 2017:
| Net taxable income (baht) | Rate |
|---|---|
| 0 – 150,000 | Exempt |
| 150,001 – 300,000 | 5% |
| 300,001 – 500,000 | 10% |
| 500,001 – 750,000 | 15% |
| 750,001 – 1,000,000 | 20% |
| 1,000,001 – 2,000,000 | 25% |
| 2,000,001 – 5,000,000 | 30% |
| Over 5,000,000 | 35% |
The RD's English pages show old numbers. Its English income tax page, last updated in March 2024, still gives a 30,000-baht personal allowance and a top band starting at 4 million baht. The Thai pages have the current 60,000 and 5 million. Use the Thai figures, or ask an accountant, before you rely on an English summary.
Other deductions exist (insurance premiums, social security contributions and more), and each has its own conditions. If you pay into the Thai system, our page on social security for foreign employees covers the contributions.
Claiming tax already paid abroad
Foreign income brought into Thailand may already have been taxed at home. The RD's 2024 guide for foreigners says the foreign tax can be credited against Thai tax only where a double taxation agreement permits it, and the credit cannot be larger than the Thai tax on that same income. In practice this means three things for the filer:
- Check that your country has a treaty with Thailand and what it says about your type of income (pensions are often treated differently from salaries).
- Get proof of the foreign tax. The RD recommends a tax payment certificate from the foreign tax authority.
- Make sure your documents are in English or Thai; the RD asks for one of the two.
The calculation itself is the part most people hand to an accountant. The residency page linked above describes the RD's online credit calculator.
Refunds, late filing and not filing
If your employer withheld more tax during the year than you owe, the annual return is where the difference is settled. The RD does not publish a refund processing time for foreigners that we could find, so ask 1161 about your case and keep your Thai bank details up to date.
Missing the deadline costs money. The RD's penalty page lists:
- a criminal fine of up to 2,000 baht for not filing PND 90, 91 or 94 on time;
- a surcharge of 1.5% per month on unpaid tax, with part of a month counted as a full month;
- a penalty of one or two times the tax if an assessment finds you did not file or under-reported (it can be reduced);
- for deliberate evasion or false statements, 3 months to 7 years in prison and a fine of 2,000 to 200,000 baht.
Not filing also leaves you without a Thai record of tax paid if you later need one, for example when your home tax office asks how your income was taxed. Retirees bringing a pension in for a retirement extension should keep that in mind. If you missed a year, talk to an accountant about filing late rather than waiting to be assessed.
Different rules apply to some people. LTR visa holders have their own tax privileges from the Board of Investment, and selling Thai property triggers withholding tax at the land office, which our guide to selling a condo explains. To check whether you crossed 180 days in a year, use our tax residency day counter.
Frequently asked questions
Do foreigners have to file a tax return in Thailand?
A foreigner with taxable income in Thailand files like anyone else: PND 91 for salary only, PND 90 for other income. A tax resident who brings foreign income into Thailand also reports it. If you are unsure whether your income requires a return, ask the RD on 1161 or a Thai accountant.
What is the deadline for the 2026 Thai tax return?
Paper returns for income earned in 2026 are due by Wednesday 31 March 2027. Online returns have a standing eight-day extension, so the online deadline is expected to be Thursday 8 April 2027. The RD had not formally announced the 2027 dates in October 2026.
How does a foreigner get a Thai tax ID number?
Apply on form L.P. 10.1 at any area revenue office, within 60 days of first earning taxable income in Thailand. Bring your passport and proof of the income. Many Thai employers arrange the tax number for new foreign staff, so ask the company first.
What is the difference between PND 90 and PND 91?
PND 91 is only for people whose sole income is employment income. PND 90 covers every type of assessable income, including rent, business income and foreign income brought into Thailand, alone or together with a salary. Both are annual returns with the same deadlines.
What happens if I file my Thai tax return late?
The RD can impose a fine of up to 2,000 baht for late filing, and unpaid tax carries a surcharge of 1.5% per month from the deadline. If an assessment finds you did not file, a penalty of one or two times the tax can be added.
Sources
- Revenue Department – Filing deadlines for tax returns (Thai) (checked October 2026)
- Revenue Department – Extension for returns filed online (Thai) (checked October 2026)
- InfoQuest – Government spokesperson on the 2026 filing deadlines (13 March 2026, Thai) (checked October 2026)
- Revenue Department – Taxpayer identification number (English) (checked October 2026)
- Revenue Department – Personal income tax rates (Thai) (checked October 2026)
- Revenue Department – Deductions and allowances, January 2025 update (Thai, PDF) (checked October 2026)
- Revenue Department – Exempt income list, July 2024 (Thai, PDF) (checked October 2026)
- Revenue Department – How do foreigners living in Thailand pay tax? (2024, PDF) (checked October 2026)
- Revenue Department – Surcharges, penalties and fines (Thai) (checked October 2026)