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A TIN (Tax Identification Number) is the number Thailand's Revenue Department uses to identify a taxpayer. Foreigners need a TIN when filing a Thai income tax return. If you receive income in Thailand, check with the Revenue Department whether you need to obtain one. In Thai paperwork you'll also see it written as Tax ID — that's just a shorter name for the same number.
Where you'll be asked for a TIN
The main place you'll meet a TIN is on a Thai tax return filed with a lawyer — form PND 90 or PND 91. You become a Thai tax resident once you spend 180 days or more in Thailand in a calendar year (section 41 of the Revenue Code). That matters because foreign income earned from 1 January 2024 onward while you were a Thai tax resident may be taxable when you remit it into Thailand, depending on the type of income and any exemption that applies. Check your position with the Revenue Department before you transfer money. It's worth working out when you become a Thai tax resident well ahead of any transfer. It isn't settled whether a Thai bank or employer will ask you for your TIN directly — check this with the bank or employer.
American account holders sometimes hear about a US TIN at the same time. That's a different, US number. Thai banks report accounts held by US persons to the Revenue Department, which passes the data on to the IRS. IRS Notice 2024-78 gives Thai banks conditional relief for 2025–2027 on qualifying pre-existing accounts missing a US TIN — but only if the bank also reports the account holder's date of birth, searches its electronic records every year and meets the notice's other conditions. None of this changes what a Thai TIN is or who needs one.
How a TIN differs from a Certificate of Residence and a work permit number
A TIN is a registration number, not a document in itself. A Certificate of Residence is different: the Revenue Department issues it for a completed tax year and a named treaty country, and only once you've filed a return for that year — the application goes in with a copy of your PND 90/91 and the tax receipt. Phuket residents apply through Regional Revenue Office 11 in Surat Thani. A work permit is a third, unrelated document: permission to work for one named Thai employer. None of the three stands in for the others.
What to check: the number on your return and at the bank
We recommend checking that the same TIN appears on your return, your tax receipt and your bank records. Keep the PND 90/91 copy and the tax receipt — you'll need both if you later apply for a Certificate of Residence, and our team checks that the right year's return is filed before we prepare that application. If the numbers don't match, ask the Revenue Department and your bank which one needs correcting, especially before you file on foreign income remitted into Thailand.
If you're not sure whether you need to file a return or get a TIN, contact us. Our lawyers will look at your income and the days you've spent in Thailand and reply within 24 hours. We agree the cost of the work in advance.
