The Thai Revenue Department has reminded companies with a 31 December 2025 year-end to file their annual corporate income tax returns by early June 2026, warning that late submissions may result in fines of up to THB 4,000 and monthly surcharges on unpaid tax. 

RF Report

The Thai Revenue Department issued a reminder on 25 May 2026 regarding the filing of annual corporate income tax returns (Form PND 50) for companies whose accounting period ran from 1 January to 31 December 2025.

The notification outlines the filing requirements, applicable deadlines, available submission channels, and penalties for non-compliance.

Filing deadlines

Companies required to submit Form PND 50 must meet one of the following deadlines depending on the filing method used:

  • Paper filing: Returns must be submitted by 2 June 2026.
  • Online filing (E-Filing): Returns must be submitted by 8 June 2026 through the Revenue Department’s electronic filing system.

The Revenue Department noted that electronic filing is available through its website and offers a more convenient and efficient method for completing tax obligations.

Available submission channels

Taxpayers may submit their corporate income tax returns through one of two channels:

  • In person at the Area Revenue Office responsible for the location of the company’s head office.
  • Online through the Revenue Department’s E-Filing platform.

Penalties for late filing

The Revenue Department warned that failure to comply with filing requirements may result in both fines and surcharges.

Taxpayers that fail to submit the required return and accompanying financial statements by the prescribed deadline may face total fines of up to THB 4,000, consisting of:

  • A fine of up to THB 2,000 for failing to file the corporate income tax return.
  • A fine of up to THB 2,000 for failing to submit financial statements.

In addition, a surcharge of 1.5% per month, or part of a month, will apply to any outstanding tax liability until payment is made.