Taxpayers can choose any 12-month tax year, although once chosen, the tax year may not be changed without approval from the tax authorities. A taxpayer's first tax year may be less than 12 months.
The annual tax return is due within 150 days following the close of the tax year. A mid-year estimated return is also required within 2-month following the first 6 months of the tax year.
Taxpayers are required to make a mid-year and year-end tax payment. The mid-year payment must be made within 2 months following the end of the first 6 months of the tax year. The mid-year payment amount is 50% of the estimated tax liability for the year.
The final tax payment is required to be made by the due date for filing of the annual tax return.
E-filing is available via the Thai Revenue Department Website (e-Filing service in Thai language).
The Thai Revenue Department has announced that effective 1 July 2020, all taxpayers are required to file their returns and make tax payments electronically. Taxpayers that submit returns via the e-filing platform are provided an 8-days extension from the normal filing due date.