In Thailand, you are in principle a tax resident once you spend 180 days in the country in a calendar year. Since 2024, the Thai tax authority considers that foreign-source income brought into Thailand by a resident may be taxable, whatever the year it was earned, subject to exceptions and the tax treaty with your country. This topic depends heavily on your situation: this guide gives the landmarks, a tax adviser decides.
Moving to Thailand quickly raises a question: where do you pay tax, and on what? This guide presents the main Thai tax residency rules and the points to check with a professional. It is deliberately general: international taxation depends on your nationality, your income, your home country and rules that keep changing.
1.Who is a tax resident in Thailand
The criterion used by Thai law is simple on paper: a person who stays in Thailand 180 days or more in a calendar year (1 January to 31 December) is considered a Thai tax resident for that year. Days add up, even across several stays.
Below that threshold, you are in principle a non-resident: only your Thai-source income (for example rent received in Thailand or a salary for work performed in Thailand) is taxable in Thailand.
Be careful: you can be considered a tax resident in two countries at once under their respective rules. The tax treaty between the two countries then decides.
2.Foreign income since 2024
This is the change that gets the most attention. Since 1 January 2024, the Thai tax authority (Revenue Department) has clarified that foreign-source income brought into Thailand by a tax resident is taxable, even if it is transferred in a different year from the one in which it was earned. Previously, only income brought in during the same year was targeted.
Important clarifications have been made:
- income earned before 2024 is in principle not affected by this new rule when transferred;
- tax treaties may provide that income already taxed in another country gives a tax credit or is only taxable in one of the two countries;
- the type of income matters (salary, public or private pension, rental income, dividends, capital gains, savings);
- implementation rules and possible exemptions continue to evolve.
This is exactly why personal advice is useful: depending on the origin of the money you transfer (old savings, pension, income of the year), the treatment can be very different.
3.Tax treaties
Thailand has signed tax treaties with many countries, including France, to avoid double taxation. They allocate taxing rights according to the type of income (pensions, salaries, property income, etc.) and provide mechanisms so you do not pay tax twice on the same income.
We do not interpret them here: how they apply depends on each income and your situation. Check whether your country has a treaty with Thailand; the texts are available on the official websites of tax authorities.
4.Filing: the calendar
- The Thai tax year is the calendar year.
- Personal income tax returns are in principle filed early the following year, with a deadline in spring; online filing usually gets a slightly longer deadline.
- To file, you need a Thai tax identification number, which you request at a Revenue Department office.
Exact dates, forms and rates are published every year by the Revenue Department.
In your home country, leaving does not necessarily end all obligations: depending on your situation, you may still need to file as a non-resident (for example for income from that country). Check with your home tax authority.
5.When to see an adviser
Professional advice is strongly recommended if:
- you plan to stay more than 180 days a year in Thailand and receive income from abroad;
- you plan to transfer substantial savings, for example to buy a home;
- you receive income from several countries (pension, rent, dividends);
- you work remotely for a foreign company from Thailand;
- you are leaving Thailand and want to know what remains taxable.
Choose a firm that knows both Thai law and that of your home country. We can point you to professionals our clients often work with.
6.A few typical situations
To make these rules more concrete, here are cases we often come across. They illustrate the questions to ask, not the answers, which depend on each case.
The retiree living year-round in Bangkok. They spend more than 180 days a year in Thailand and have their pension transferred every month. Questions for the adviser: is the pension taxable in the home country, in Thailand or in both under the treaty? Do they need to file in Thailand? How can double taxation be avoided?
The couple splitting the year between two countries. They spend less than 180 days in Thailand. In principle they are not Thai tax residents, but the count must be tracked carefully, as a few extra weeks can change the situation.
The buyer transferring savings. They bring in a large sum to buy a condo. Questions to ask: were the savings built up before 2024? How can their origin be proven? Does the transfer have a tax consequence in Thailand, given their tax residency in the year of transfer?
The remote employee. They work from Bangkok for a foreign company. Beyond tax, this situation also raises the question of visas and the right to work in Thailand, to be examined before moving.
7.Good everyday habits
- Keep a record of your days in the country: passport stamps are the reference, but a simple table avoids counting errors.
- Separate your accounts: one for older savings, one for current income; it makes proving the origin of funds easier.
- Keep your records for several years: bank statements, pension statements, foreign tax notices.
- Review your situation every year with your adviser, as the rules change.
8.How to choose your adviser
A good adviser for an expatriate in Thailand should:
- know both systems: Thai tax law and that of your home country, as well as the treaty linking them;
- explain in writing their reading of your situation and the assumptions made;
- tell you their fees in advance, for a first meeting as well as for an annual return;
- speak your language, or at least English, so you understand what you sign.
Prepare your first meeting with a list of your income by country, your dates of presence in Thailand, your bank accounts and planned transfers. One well-prepared hour is often worth more than several vague exchanges.
9.In short
- 180 days in the calendar year: you are in principle a Thai tax resident.
- Foreign income brought into Thailand may be taxable, under rules clarified since 2024.
- The tax treaty between your country and Thailand in principle avoids double taxation.
- Keep proof of where your funds come from, and get advice before large transfers.
For buying a home, see also our guide Buying a condo in Thailand as a foreigner.
Frequently asked questions
How many days in Thailand make you a tax resident?
In principle 180 days or more in a calendar year, adding up your stays. You may also remain a tax resident of another country: the tax treaty then decides.
Is my foreign pension taxable in Thailand?
It depends on the type of pension (public or private), whether it is brought into Thailand and the tax treaty between your country and Thailand. This is typically a question for an adviser.
Are savings built up before I arrived taxed when I transfer them?
Income earned before 2024 is in principle outside the new rule on remitted income. Keep proof of the origin and date of the funds, and have your case checked by a professional.
Do I need a Thai tax number?
Yes if you need to file a return in Thailand. You apply for it at a Revenue Department office.
General information updated on 10 October 2026; check your contract and with the Find Easy team.
