Overview
A double taxation agreement, or DTA, is a treaty between two countries that settles which one gets to tax a given piece of income, and provides a mechanism so the same money isn't taxed twice. Thailand currently has DTAs in force with 61 countries, including the UK, the US, Australia, Canada and Singapore.
Section 1
How the Relief Actually Works
The Foreign Tax Credit
Thailand grants a foreign tax credit equal to the lesser of two figures: the tax you actually paid on that income abroad, or the tax Thailand would have charged on the same income under its own rules. The credit reduces your Thai tax bill by that amount — it doesn't refund tax paid overseas, and it doesn't automatically mean zero tax is due in Thailand.
Each DTA is its own document, and different income types — pensions, dividends, rental income, employment income — are often treated differently within the same treaty. There is no single universal answer; the specific treaty with your specific country governs.
Section 2
Claiming It: Three Steps
Get a Certificate of Residence
Issued by your home country's own tax authority (HMRC in the UK, the IRS in the US), confirming you're tax resident there for the relevant year.
Declare the income and the tax already paid
On your Thai return, report the foreign income you remitted and the tax you've already paid on it at source.
Attach the DTA relief forms
Filed alongside form PND.90, these formally claim the treaty relief rather than leaving it to be assumed.
US Citizens Specifically
Worth Doing
This guide explains general principles as understood in mid-2026 and is not personalised tax advice. The terms of your specific treaty govern your situation — always confirm with a qualified Thai tax professional before relying on treaty relief.
Speak with Our Team
Need Help Claiming Treaty Relief?
If you need help understanding how your specific treaty applies or preparing the paperwork, our team can point you in the right direction.
