Thailand tax on foreign-sourced income 2025: what residents and long-stayers must know

Thailand tax on foreign-sourced income 2025: what residents and long-stayers must know

Introduction

If you live in Thailand long enough to become a tax resident, the way you move money from overseas can create a Thai personal income tax bill. This guide explains the current rule for Thailand tax on foreign-sourced income 2025, what changed from 2024, what is merely proposed but not yet law, and how to plan remittances, records, and credits under Thai rules. All core points are verified against the Revenue Department’s English materials and the underlying Revenue Code.

Who is a Thai tax resident

You are a resident if you are in Thailand for 180 days or more during a calendar year. Residents are liable for income from Thai sources and for foreign-sourced income that is brought into Thailand. The Revenue Department’s English pages and guides state the 180-day test and the resident scope clearly.

Thailand tax on foreign-sourced income 2025: the rule in force

From 1 January 2024 onward, if a Thai tax resident earns assessable income from employment, business, or property outside Thailand and brings that income into Thailand, it is taxable in the year of remittance, regardless of when it was earned. The Revenue Department’s 2024 English explainer for foreigners and Section 41 materials set this out; professional alerts summarize the Departmental Instructions No. Por.161/2566 and Por.162/2566 that drove the change.

Grandfathering reminder: Income earned before 1 January 2024 that is remitted after that date remains outside the new rule according to the Department’s guidance on the 2023 instructions. Verify your facts and documentary trail before relying on this.

What counts as foreign-sourced income and how remittance is taxed

The rule covers assessable income in Section 40 categories, including salary, business profits, interest, dividends, rent, and capital gains where applicable under Thai law. If you remit part of the foreign income, only that portion is taxable in Thailand for that year. The Revenue Department’s 2024 English PDF for foreigners confirms apportionment on partial remittances and explains foreign tax credit mechanics.

Reporting, deadlines, and credits

• Return due dates: Paper return by 31 March and e-filing typically by early April of the following year. Big-Four executive tax guides and RD materials reflect these deadlines.

• Foreign tax credits: Thai residents may credit eligible foreign taxes against Thai tax subject to treaty and Thai rules. The RD’s English flyer for foreigners highlights the foreign tax credit concept and documentation expectations.

Proposed relief in 2025: not law yet

In mid-2025, the Revenue Department discussed a draft change that would exempt foreign-sourced income remitted within the same year it is earned or the following year. As of today, this is only a proposal pending legislation or a royal decree. Do not plan as if it were enacted. Industry coverage and legal updates describe the draft but confirm it is not yet in force.

Practical planning for residents and long-stayers

1. Evidence of timing and source: Keep bank statements and deal files that show when income was earned and when it was brought into Thailand. The RD’s 2024 flyer notes apportionment when only part is remitted, which requires clear records.

2. Treaties and credits: Check if a Double Taxation Agreement applies and preserve proof of foreign tax paid for credit in Thailand. The RD’s materials flag documentation for treaty relief.

3. Cash vs. in-kind: Plan how and when you remit cash vs. using offshore expenses to avoid unnecessary remittances that could become taxable in Thailand.

4. Category mapping: Classify income correctly under Section 40 to apply the right Thai rules. The RD’s English code pages help orient categories and definitions.

5. Calendar math for residency: Track days to understand when you become a resident under the 180-day test.

Common mistakes we fix

• Assuming the old practice applies if you simply wait one year to remit. Since 1 January 2024, waiting no longer avoids tax upon remittance.

• Failing to document partial remittances and then losing the ability to apportion. The RD flyer explains partial-remittance apportionment.

• Treating media reports of 2025 proposals as enacted law. As of now, relief remains a draft concept.

How GENTLE LAW IBL helps

Our one-stop team integrates immigration, corporate, and personal tax. We map your income streams to Section 40, structure remittances, document foreign tax credits, and coordinate with your home-country advisers so your Thai filings are clean and defensible.

Conclusion and next steps

The operative rule for Thailand tax on foreign-sourced income 2025 is simple: if you are a Thai tax resident and you bring post-2023 foreign income into Thailand, expect Thai tax in the year of remittance unless a specific exemption applies. For a fact-checked remittance and filing plan tailored to your situation, contact GENTLE LAW IBL.

📩 Book a consultation: https://gentlelawibl.com