Chiang Mai Living Guide

Money & taxes

Thai taxpayer numbers and income-tax returns

Check your TIN, organize income records, choose the right tax-year forms and keep filing records.

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File folders for organising income records and filing receipts
File folders for organising income records and filing receipts · Shoplet Office Supplies · Photo source · CC BY-SA 3.0 · Resized and converted to WebP; display may crop.

Start with these three things

  1. Foreign applicants should consult the tax office responsible for their address about a taxpayer number. The Revenue Department identifies form LP10.1.
  2. PND90 and PND91 are for different income types. Do not use the employment-only form when you also have other income.
  3. The official 2026 list includes a foreign-income attachment. The annual return and following year’s e-filing deadline remain unverified; check the Revenue Department’s latest guidance when filing.

Steps

"Tip" marks a planning suggestion, not an official rule.

  1. Tip If applying for the first time, check whether you already have a Thai taxpayer number. Locate previous payroll and filing records to avoid a duplicate application.
  2. Ask the responsible Area Revenue Office or Branch about obtaining a number or correcting a name or birth-date mismatch. The Revenue Department FAQ describes the LP10.1 procedure.
  3. Tip Identify the tax year, total Thai and foreign income, withholding and remittances, then ask the office whether a return is required and which form to use.
  4. Tip Keep the return, attachments, receipt of filing and payment confirmation together for that tax year.

What to prepare

"Tip" marks a planning suggestion, not an official rule.

  • Tip A passport, address evidence, any existing TIN, income statements and travel and remittance records can help an enquiry. Ask the office which originals, copies and address documents it actually requires.
  • Foreign-tax-credit guidance calls for evidence of foreign income and tax paid. Check translation and certification requirements for Japanese documents beforehand.

Where to ask

Thai Revenue Department / Area Revenue Office or Branch serving your address

These are the offices identified by the Revenue Department for foreign applicants seeking a taxpayer number.

Office hours are not yet confirmed. Confirm before visiting, and ask the same office about online registration.

Things to watch for

  • Do not use a 2025 form as evidence of 2026 filing conditions or deadlines. The official lists are organized by year.

Planning tips (not official rules)

  • A small amount of tax due does not by itself establish that no return is needed. Give the office your income types and amounts and ask about the filing obligation.
  • If account registration fails, request a check of the registered details rather than changing the spelling of your name or date of birth to make it work.

Income types and forms

The Revenue Department’s 2025 English list distinguishes PND90, for income beyond employment alone, from PND91, for employment income only under section 40(1). Ask about the classification of foreign pensions or rental income before selecting a form.

Planning tips (not official rules)

If you started renting out property or running a business partway through the year, ask whether any interim procedure is needed in addition to the annual return. Do not choose only by a familiar form name before establishing the income category.

Foreign income and tax credits

The Revenue Department publishes a personal foreign-tax-credit calculation aid and an English guide. They can help organize the country, year and type of income and distinguish foreign tax paid from amounts brought into Thailand.

Official document guidance describes legalization of foreign-government documents and Thai translation of documents in languages other than Thai or English. Ask the responsible office how to submit them while collecting the records.

Tax year and deadline

Planning tips (not official rules)

Ask which tax year, whether filing is on paper or electronically and whether payment has the same deadline. Save the official page or written reply. Do not infer an extension from a previous year’s blog post.

Confirm the forms, deadline and documents for the relevant tax year with the responsible Thai Revenue Department office.

The annual filing deadline for 2026 income is not yet confirmed. Check the Revenue Department’s announcement before planning your filing.

Sources & dates checked

  1. OfficialRevenue Department of Thailand ไขปัญหาRevenue Department of Thailand · Checked 2026-10-11
  2. Officiale-Form: Personal Income Tax 2025Revenue Department of Thailand · Checked 2026-10-11
  3. Officiale-Form: Personal Income Tax 2026Revenue Department of Thailand · Checked 2026-10-11
  4. OfficialDocuments for claiming Foreign Tax Credit (FTC) in ThailandRevenue Department of Thailand · Checked 2026-10-11
  5. OfficialRevenue Department of Thailand เครื่องมือช่วยคำนวณเครดิตภาษีสำหรับผู้มีเงินได้จากต่างประเทศ (กรณีภาษีเงินได้บุคคลธรรมดา)Revenue Department of Thailand · Checked 2026-10-11
  6. OfficialManual for Foreign Tax Credit Calculation Tool (Personal Income Tax)Revenue Department of Thailand · Checked 2026-10-11
  7. ReferenceJETRO 税制 | タイ - アジア - 国・地域別に見る - ジェトロJETRO · Checked 2026-10-11