Tax Identification Number in Thailand: How to Get a Thai TIN.

What a Thai tax identification number is

A tax identification number in Thailand is the 13-digit number the Revenue Department uses to identify a taxpayer, and most people in Thailand already hold theirs without applying for anything. A Thai national's national ID card number serves as their taxpayer identification number. A registered Thai company's juristic person registration number serves as its own.

The people who still have to apply are the ones holding neither: foreigners, unregistered partnerships and bodies of persons, undivided estates, and foreign companies operating in Thailand.

The legal basis is one short section. Section 3 Undecim of the Revenue Code gives the Director-General the power to require taxpayers and payers of income to obtain and use a tax identification number, under rules he sets with the Minister's approval and publishes in the Royal Gazette. The text sits in the general provisions of the Revenue Code.

The digit count is where the department's own pages disagree with each other. Its Thai-language clarification on the 13-digit taxpayer number records the switch: a Director-General's Notification dated 11 January 2012, in force from 1 February 2012, moved individuals onto their national ID number and companies onto their Department of Business Development registration number, both of which run to 13 digits. Holders of the previous 10-digit number could keep using it on other documents until 31 January 2013, though not on tax returns.

The department's English tax identification page still describes the number as 10 digits. That page was last updated in March 2014 and the sentence was never brought forward. Thirteen digits is the current position, and the number on a Thai ID card is the easiest place to see it.

Who needs a tax identification number in Thailand

The Revenue Department's tax identification page sets out who applies, when, and on which form.

Assessable income is the Revenue Code's term for income it brings into charge, in cash or in kind. Salary, rent, professional fees and dividends all count, and so does foreign income that a tax resident brings into Thailand.

Two groups sit outside the requirement. The first is anyone who already holds a personal identification number under the civil registration law. For a Thai national that is the ID card number, and it already does the job. The second is narrow: a foreigner present in Thailand for no single period longer than 14 days, and for no more than 90 days in aggregate within a tax year, does not have to apply.

What triggers the duty is income rather than intention. Someone retiring in Thailand on a retirement visa who derives no assessable income has nothing to apply for, and the same person has a 60-day clock running from the moment assessable income arrives.

Employers sit in the last row of the table. A payer of income with a withholding duty applies on L.P.10.4 within 60 days before the payment date, although a registered Thai company already carries its own number and uses that instead. The withholding and payroll duties that follow are part of hiring your first employees in Thailand.

Two different clocks: 60 days and 180 days

The 60-day deadline is counted from the date assessable income is first derived. It is not counted from the day someone becomes a tax resident, a mix-up that sends people to the office in the wrong year.

Tax residency runs on its own clock and decides something else. A person in Thailand for periods aggregating more than 180 days in a calendar year is a resident for tax, as the Revenue Department's personal income tax overview states. A resident is taxed on income from sources in Thailand and on foreign income brought into Thailand. A non-resident is taxed on Thai-source income only. What residency then means in practice is the subject of Thailand tax residency and income tax for foreigners.

A non-resident with Thai-source income can therefore need a number in a year they never come near 180 days. Residency changes what goes on the return rather than whether a number is needed, and that side is covered under personal income tax in Thailand.

Individuals: applying on form L.P.10.1

The route for an individual is in person, on paper, at a revenue office.

1. Fix the trigger date. The 60 days run from the date assessable income was first derived, so that date decides whether an application is on time.
2. Download the form. The Revenue Department's form download page carries L.P.10.1 through L.P.10.4 as PDF and ZIP files, in Thai.
3. Gather the documents. For a new number, L.P.10.1 asks for a photocopy of the applicant's alien certificate or passport, or a national ID card or government officer identification card where there is one, together with the house registration book for the taxpayer.
4. File it at an area revenue office. In Bangkok the application goes to the area revenue office or area revenue branch office with jurisdiction over the applicant's domicile, and in other provinces to the area revenue branch office for that domicile. An individual may also file at any area revenue office or branch office, regardless of where they are domiciled.

That last point saves a journey. The Board of Investment's long-term resident visa FAQ makes it in plainer words for LTR holders: someone on that visa with income in Thailand can apply for a taxpayer identification number at any Revenue Department office nationwide.

There is no verified online route for an individual foreigner. The department's tax identification page describes an internet application at tinreg.rd.go.th for Thai juristic persons only, and in Thai only. No official page describes an English-language online application for an individual, so the counter remains the route.

Companies and partnerships: the DBD number is the tax ID

A registered Thai company or juristic partnership does not apply for anything. The 13-digit juristic person registration number issued by the Department of Business Development at registration is the entity's taxpayer identification number, so registering a company in Thailand produces the tax ID as a by-product of the incorporation itself. The professional side of that work, from name reservation through to the memorandum of association, sits under company registration in Thailand.

Directors looking for the number afterwards can find it on the Department of Business Development's public DataWarehouse registry, which searches on either the company name or the juristic person registration number and returns status, address, registered capital and change history.

Foreign companies are the exception. The Revenue Department's income tax guide for foreign companies states that a foreign company carrying on business in Thailand, whether it sets up a branch or an office, must apply for a tax identification number on form Lor Por 10.3 with supporting documents, submitted to the Area Revenue Office within 60 days from the date of registration or operation. What follows for that entity is corporate income tax in Thailand.

L.P.10.3 asks for more paperwork than the individual form. Alongside the application it takes, among other things, the house registration for the head office premises, the certificate of incorporation, the certificate of carrying on business in Thailand, a joint venture contract where there is one, the contract appointing an employee or agent in Thailand, and identity documents for the authorised managing director, managing partner, employee or agent.

What it costs and how long it takes

The Revenue Department publishes no application fee for a tax identification number, on its tax identification pages or on its form download page. Pages elsewhere that state the application is free are asserting something the department has not published, and the honest position is that no official figure exists to quote.

Professional fees are a separate line, and a private one. Where an accountant or tax adviser prepares and files L.P.10.1 or L.P.10.3, that fee is set by the firm, and the Revenue Department publishes no schedule for advisers and no survey of market rates. A firm listed among tax consultants in Thailand will quote for the specific application.

Processing time has the same gap. No official Revenue Department page commits to a turnaround for a tax identification number application, so there is no government figure to give. The only published timings are the deadlines themselves.

Accounts that promise a number the same day are describing one office on one day rather than a published standard, which is a useful thing to know before planning a trip around one.

Missing the 60-day deadline

Section 3 Duodecim of the Revenue Code sets the penalty for failing to comply with the Director-General's announcement made under Section 3 Undecim: a fine of not more than 2,000 baht. That is the whole of the direct consequence attached to the number.

The exposure that matters usually sits behind it. Someone who missed the 60-day deadline has often also missed the returns the number was needed for, and unfiled returns and unpaid tax carry their own surcharge and penalties on a scale the 2,000 baht does not reflect.

Deciding whether a particular payment started the clock, and what the position is for years already closed, is a question for a professional rather than a form. A tax adviser can check the trigger date and the years exposed before anything goes in.

What the number is used for afterwards

Once issued, the 13-digit number identifies the taxpayer on returns, on withholding tax certificates and on tax invoices. For an individual it is the number the annual personal income tax return is filed under, as how to file a tax return in Thailand sets out, due by the last day of March following the tax year, with a half-year return by the last day of September for certain categories of income. For a company it runs through the whole corporate filing year, which is set out in the filing deadlines that follow.

When to bring in a tax adviser

A foreigner with one Thai employer and one source of income generally completes L.P.10.1 unaided, and the counter at the area revenue office is the right place for the questions that come up on the day.

Paid help earns its fee where the trigger date is genuinely unclear: income arriving from several sources in the same year, a first year of Thai residency, foreign income remitted part-way through a year, an undivided estate under administration, or a foreign company working out whether an office in Bangkok is carrying on business in Thailand at all. Each of those moves the date the 60 days start from, and the date is the whole question.

Company owners have a second reason. The number, the books and the filings have to line up from the first accounting period, which is where Thai accounting requirements begin. For the application itself, a tax lawyer in Thailand or a licensed accountant can check the position before the form goes across the counter.