Tax residence in Thailand: the 180-day rule and what it actually triggers

Thailand decides tax residence by counting days and nothing else. Under Section 41 paragraph 3 of the Revenue Code, anyone present in Thailand for a period or periods aggregating 180 days or more in a tax year (the calendar year, 1 January to 31 December) is a tax resident for that year. The days need not be consecutive, and nationality, visa type and immigration status are all irrelevant. The Revenue Department's own worked examples make the edges clear: 184 scattered days makes you resident, 179 days spread across the year does not, and 250 consecutive days split 100 in one calendar year and 150 in the next makes you resident in neither year, because the test runs per calendar year.

What residence triggers: residents are taxable on income from sources in Thailand however and wherever it is paid, plus foreign-sourced income under the remittance rules in force since 2024. Non-residents are taxed only on Thai-source income. Residence in a given year is also what lets you claim relief under Thailand's tax treaties as a Thai resident, including foreign tax credits.

Two pieces of forum folklore worth correcting: crossing 180 days does not by itself mean you owe tax or must file — that depends on having assessable income above the filing thresholds — and staying under 180 days does not shield Thai-source income, which is taxable regardless of residence.