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Filing6 min read

How to File a Thai Tax Return as an Expat: Step-by-Step Guide (PND 90/91)

Published: March 1, 2024

This article is for informational purposes only and is based on publicly available Thai Revenue Department guidance and the Revenue Code. Tax rules change — verify current regulations at rd.go.th or consult a licensed Thai tax advisor before making financial decisions.

Who Must File?

You must file a Thai tax return if:

  • You are a Thai tax resident (180+ days in Thailand)
  • Your annual income exceeds 120,000 THB (single) or 220,000 THB (married)
  • You have Thai-sourced income subject to tax

Filing Deadline

The deadline for filing your annual tax return is March 31 of the following year. For example, 2024 income must be filed by March 31, 2025.

Online filing via the RD Smart Tax app may extend this deadline by 8 days.

Required Documents

  1. Tax Certificates (Withholding Tax Certificates)
    • From your employer (Form 50 Tawi)
    • From banks (interest income)
    • From other payers
  2. Personal Documents
    • Thai ID or passport
    • Tax ID number
  3. Supporting Documents
    • Marriage certificate (for spouse allowance)
    • Birth certificates (for child allowance)
    • Insurance premium receipts
    • Donation receipts

Filing Methods

Online (Recommended)

  • RD Smart Tax app
  • E-filing via rd.go.th
  • Faster processing and longer deadline

In Person

  • Visit your local Revenue Department office
  • Bring all original documents
  • Submit before March 31

Common Mistakes to Avoid

  1. Missing the deadline
  2. Forgetting to claim allowances
  3. Not reporting all income sources
  4. Incorrect calculations
  5. Missing required attachments

Sources & Official References

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