Do I need to file a Thai tax return if my income is all from abroad?

This question has changed dramatically since Revenue Department Order No. P.161/2566, effective 1 January B.E. 2567 (2024). The short answer for tax years 2024 onwards: yes, you probably do, if you are tax-resident in Thailand and you remit any of your foreign income into the country.

Tax residency. Under Section 41 of the Revenue Code, you are a Thai tax resident if you are present in Thailand for 180 days or more in a calendar year (1 January – 31 December). Residency is per calendar year — leaving on 30 December and returning on 2 January is two separate years.

The old rule (pre-2024). Foreign-source income was only taxable if remitted into Thailand in the same calendar year it was earned. Many long-term residents used this to remit prior-year savings tax-free.

The new rule (2024 onwards). Foreign-source income remitted into Thailand is taxable regardless of which year it was earned, if you are tax-resident in the year of remittance. The only safe-harbour is income earned in years before you became tax-resident.

What you need to do:

• If you are tax-resident and remit any income from abroad in 2024 or later, file form ภ.ง.ด.90/91 (PND.90/91) with the Revenue Department (กรมสรรพากร) by 31 March of the following year (or 8 April if filing online).
• Obtain a Tax Identification Number (TIN) from any Revenue Office — free, takes about 30 minutes, requires only passport and a Thai address.
• Claim relief under the relevant Double Taxation Agreement (DTA). Thailand has DTAs with 60+ countries. Tax already paid at source can usually be credited.

Special cases:

• LTR (Long-Term Resident) visa holders in the “Wealthy Global Citizen,” “Wealthy Pensioner,” and “Work-from-Thailand Professional” categories enjoy a specific exemption on remitted foreign income under Royal Decree No. 743 — still confirm with a Thai accountant.
• Income that stays abroad (never remitted) is not subject to Thai income tax under current law, even if you are tax-resident. This is a major planning point for those with offshore brokerage accounts.

The Revenue Department has been increasing enforcement: banks now flag inbound transfers above THB 2 million for review. Speak to a Thai-qualified tax adviser before remitting large sums.