Do I need to file a Thai tax return?

Three questions decide it: how many days you spent in Thailand this year, whether you earned anything from a Thai source, and whether you brought foreign income into the country. Answer those and you know whether you owe the Revenue Department a form, whether you owe it money, and which of the two forms you need.

This is written for individuals: retirees, remote workers on a DTV, people on a Thai payroll, and anyone with a Thai brokerage account. It covers tax year 2026, filed by the end of March 2027, and notes where 2025 differed. This is not advice for your specific situation. It is the arithmetic you need before you decide whether to pay someone for that advice.

Question 1: were you in Thailand for 180 days or more?

Count every day you were physically in Thailand during the calendar year. The days you arrived and left both count, and trips don't need to be consecutive. Reach 180 and you're a Thai tax resident for that year. The test is in Section 41 of the Revenue Code.

Residency changes what's taxable. A non-resident owes Thai tax only on income from a Thai source: a Thai salary, Thai rent, Thai dividends. A resident owes tax on Thai-source income plus any foreign income earned from 1 January 2024 onward that they bring into Thailand, in the year they bring it in. That second part is the rule that changed in 2024 (Order Por.161/2566, Thai), and it drives most of the confusion around this topic.

Under 180 days with no Thai-source income? You can stop reading. Nothing to file. Keep your passport stamps or an entry-exit log in case anyone asks later.

Question 2: did you have Thai-source income?

Salary from a Thai employer, fees for work done in Thailand, rental income from a Thai condo, interest from a Thai bank, dividends from SET-listed shares — all of it is assessable whether you're resident or not.

Two of those come with a shortcut. Thai banks withhold 15% on interest, and Thai companies withhold 10% on dividends; you can treat that withholding as final and leave the income off your return entirely. Whether you should is a separate question — someone in a low bracket often gets money back by including it instead. Example E below walks through the numbers.

Question 3: did you bring foreign income into Thailand?

This only applies if you answered yes to question 1. As a resident, foreign income you earned from 2024 onward becomes taxable in Thailand in the year you remit it. Salary paid to a foreign account, a pension, dividends from a foreign broker, rent from a house back home — none of it is taxed while it stays abroad. Transfer it to your Thai account, withdraw it at a Thai ATM, or spend it here on a foreign card, and the amount you brought in becomes assessable income for that year. The Revenue Department's Q&A on the 2024 rules (Thai) walks through when remitted money becomes assessable.

Money you had before 1 January 2024 is exempt when remitted, no matter when you move it (Order Por.162/2566, Thai). This is the single most useful fact for retirees living off savings, which is exactly why a bank statement from December 2023 is worth keeping forever.

The filing thresholds

Having assessable income doesn't always mean you must file. Section 56 of the Revenue Code sets minimums:

Notice the gap between filing and paying. You file because your income crossed ฿60,000 or ฿120,000. You pay only if income after expenses and allowances exceeds ฿150,000, and a single person on ฿300,000 of employment income gets ฿160,000 of expense deduction and personal allowance before that threshold even applies. So that person must file and owes nothing. That's normal, and a nil return is how you show the Revenue Department you looked.

Which form: PND 90 or PND 91

PND 91 covers people whose only income is employment income under Section 40(1), which includes pensions. PND 90 covers everyone else: any other income type, or employment income mixed with anything else. A retiree with only a foreign pension remitted files PND 91, though some advisers put foreign-sourced income on PND 90 and the Revenue Department accepts either. Add Thai bank interest you choose to declare, or foreign dividends you remitted, and it becomes PND 90.

Deadline for tax year 2026: 31 March 2027 on paper, 8 April 2027 if you e-file. The eight-day e-filing extension is granted in three-year blocks and the current one runs to January 2027, so the April 2027 date assumes a renewal — which has happened every time so far.

Six worked examples

The brackets used below: 0% to ฿150,000, 5% to ฿300,000, 10% to ฿500,000, 15% to ฿750,000, 20% to ฿1,000,000, 25% to ฿2,000,000, 30% to ฿5,000,000, 35% above. Employment and pension income gets a 50% expense deduction capped at ฿100,000. Everyone gets a ฿60,000 personal allowance. Anyone 65 or older gets the first ฿190,000 of income exempt on top.

A. Retiree, 68, UK state pension, 330 days in Thailand

Remits ฿600,000 of pension during the year. Resident. The UK-Thailand treaty leaves the state pension taxable in Thailand — only UK government-service pensions are exempt. Assessable income ฿600,000, so this person must file PND 91.

Age exemption ฿190,000, expenses ฿100,000, personal allowance ฿60,000. Net ฿250,000. Tax: 5% on the ฿100,000 above ฿150,000 is ฿5,000. Health insurance premiums, up to ฿25,000, would bring that lower.

B. Retiree, 70, living on savings from 2019

Remits ฿800,000 from an account holding that money since before 2024. Not assessable. Fixed-deposit interest of ฿30,000 had 15% withheld and is treated as final. Most advisers read this as no filing obligation. Keep the pre-2024 statement showing the balance, and the transfer records — the burden of showing the money is old capital sits with you.

C. DTV remote worker, 200 days, salary paid abroad

Earns the equivalent of ฿2,000,000 from a foreign employer into a foreign account. Remits ฿400,000 for rent and living costs. Resident, so the ฿400,000 is assessable in Thailand; the ฿1,600,000 left abroad isn't, this year. Must file PND 91 — foreign employment income is still Section 40(1).

Expenses ฿100,000, allowance ฿60,000. Net ฿240,000. Tax: 5% on ฿90,000 is ฿4,500. If the home country taxed the same salary and has a treaty with Thailand, a foreign tax credit may wipe that out (see the Revenue Department's English guide to the foreign tax credit). Expect to attach the foreign assessment and possibly visit the area office; several filers report the online form handling the credit poorly.

D. Employee on a Thai payroll, ฿1,200,000 a year

The employer withholds tax monthly and hands over a 50 Tawi certificate in January. Filing is still mandatory; withholding is a prepayment, not a substitute. PND 91 if that's the only income.

Expenses ฿100,000, allowance ฿60,000, provident fund ฿60,000 (5%), social security ฿10,500 (the 2026 cap, up from ฿9,000 in 2025). Net ฿969,500. Tax ฿108,900. RMF and Thai ESG purchases before 30 December could cut that substantially.

E. Resident investor with ฿200,000 of SET dividends, no other Thai income

Brokers withheld 10% (฿20,000). Treating that as final means no return. But for a Thai tax resident, the imputation credit for dividends from Thai companies taxed at the 20% corporate rate adds ฿50,000 of notional income (200,000 × 20/80) and ฿50,000 of credit. Grossed-up income ฿250,000, less the ฿60,000 allowance, gives net ฿190,000 and tax of ฿2,000. Credits total ฿70,000 (฿50,000 imputation plus ฿20,000 withheld), so about ฿68,000 comes back as a refund.

F. 150 days in Thailand, ฿2,000,000 remitted from foreign salary

Not resident. Foreign income is out of scope regardless of how much was remitted. No Thai-source income, so no return. The only thing worth keeping is proof of the day count.

What happens if you don't file

The Revenue Department hasn't been knocking on retirees' doors, and enforcement against individuals has taken a back seat to other priorities. That said, the penalties on the books are real: a fine of up to ฿2,000 for a late or missing return, a surcharge of 1.5% per month on unpaid tax capped at the tax due, a penalty equal to the tax for an incorrect return, and double the tax if you never filed at all. Both penalties can be reduced on request. Immigration has been asked repeatedly whether it will start requesting tax returns for extensions; it doesn't, as of this writing.

The practical risk runs the other way. If you ever need a Thai tax return — some banks ask for one to open an investment account, and some countries want proof you paid tax in Thailand to exempt you at home — a clean history of nil returns is far easier to produce than three years reconstructed from old statements.

What to keep during the year

The return itself takes an hour. The evidence takes a year to assemble unless you keep it as you go: an entry-exit day count, every transfer into Thailand with its date and source account, bank statements covering December 2023 if you rely on pre-2024 savings, 50 Tawi certificates, insurance and fund purchase confirmations, and dividend and interest slips.

ThaiWealth AI reads your statement PDFs and sorts the transactions into categories, so you can see what you spent and where money came from without combing through the raw PDF yourself. It also keeps a deduction ledger for RMF, SSF, insurance premiums, and donations, gathered in one place instead of scattered across confirmation emails. It doesn't total withholding tax or generate a filing-ready form yet — that part is still typed in by hand. Try the free tax calculator first if you just want a number.

Frequently asked questions

Does the 180-day rule count arrival and departure days?

Count both. The test is physical presence in Thailand for 180 days or more, aggregated across the calendar year, not consecutive.

I'm on a retirement visa and only bring in my pension. Do I file?

If you're resident and the pension you remitted exceeds ฿120,000 in the year, yes — PND 91. Whether you owe anything depends on your age, the treaty with your home country, and your deductions. Government-service pensions from most treaty countries are exempt; state and private pensions usually aren't.

Are credit card purchases and ATM withdrawals in Thailand a remittance?

The Revenue Department's reading, shared by most practitioners, is that spending foreign income in Thailand by any means brings it in. Cards and ATM withdrawals funded by post-2023 income count. Spending pre-2024 savings doesn't.

Do I need a Thai tax ID number to file?

Yes. Holders of a pink ID card or yellow house book use that 13-digit number. Everyone else applies at the area Revenue Office with a passport, visa, and proof of address, and receives a separate 13-digit number. Do this before March — offices get busy.

Was the 'remit in the same year, pay no tax' rule passed?

No. It was announced in May 2025 and hasn't been gazetted as of this writing. The rule in force is the one from 1 January 2024: foreign income earned from that date is taxable when remitted.

Can I e-file in English?

The e-filing system at the Revenue Department's website is in Thai. Foreigners file through it with a Thai tax ID and a Thai phone number, usually with a translation extension or someone helping.