Thailand taxes personal income (PIT) on a progressive scale from 0% to 35%, applied to net income after deductions and allowances. Tax residents (anyone present 180+ days in a calendar year) are taxed on Thai-sourced income and, since a Revenue Department reinterpretation of Section 41 effective 1 January 2024 (Por. 161/162), on foreign-sourced income remitted into Thailand in any year it is remitted — not just the year earned, as under the pre-2024 rule. Non-residents are taxed only on Thai-sourced income. A further move toward taxing residents' worldwide income regardless of remittance has been publicly discussed but had not been enacted into law by mid-2026 — only the remittance-basis change is currently in force.
This is the single biggest tax change affecting foreign retirees, remote workers and Long-Term Resident (LTR) visa holders in Thailand since 2024 — the timing and structure of money transfers into Thailand now directly determines Thai tax exposure on foreign income.
Tax residency is triggered by 180+ days' physical presence in Thailand in a calendar year.
Since 1 Jan 2024, tax residents owe Thai PIT on foreign-sourced income remitted into Thailand in any tax year, regardless of when it was earned (Revenue Department Order Por. 161/162).
LTR (Long-Term Resident) visa holders in the Wealthy Global Citizen, Wealthy Pensioner and Work-from-Thailand Professional categories are exempt from tax on foreign-sourced income brought into Thailand, by royal decree — a major planning advantage over ordinary residents.
A standard personal allowance of THB 60,000 plus an employment income deduction (50% of income, capped at THB 100,000) apply before the progressive bands.
Annual PIT returns (PND 90/91) are due by 31 March of the following year (8 April if filed online).
Steps
Determine residency status — Count days physically present in Thailand in the calendar year; 180+ days makes you tax resident on the remittance basis described above.
Track remittances, not just earnings — Since the 2024 rule change, what matters for foreign income is the year money is brought into Thailand, not the year it was earned — keep records of source and timing of every transfer.
Apply deductions and allowances — Personal allowance, employment income deduction, and other eligible deductions (spouse, children, life insurance, provident fund, retirement funds) reduce net assessable income before the progressive bands apply.
File PND 90/91 — Residents with assessable income file by 31 March (paper) or 8 April (e-filing) of the year following the tax year.
Timelines
Annual PIT filing deadline (paper): 31 March following the tax year
Annual PIT filing deadline (e-filing): 8 April following the tax year
Required Documents
Tax identification number (Tax ID) from the Revenue Department
Withholding tax certificates (50 Tawi)
Records of foreign income and remittance dates/amounts
Bank statements evidencing transfers into Thailand
Common Mistakes
Assuming pre-2024 rules still apply — foreign income earned in an earlier year and remitted later is now taxable in the year of remittance, not exempt.
Overlooking that LTR visa categories carry a specific royal-decree exemption for remitted foreign income that ordinary residents (including retirement/marriage visa holders) do not get.
Miscounting days of presence — partial days and short trips out of Thailand still count toward or against the 180-day threshold depending on entry/exit stamps.