All legal entities registered in Thailand needs to submit a mid-year (or interim) corporate income tax return (Form PND 51) to the Revenue Department within 2 months after the end of the first 6 months of their accounting year.

A company is obliged to estimate its annual net profit as well as its tax liability and pay half of the estimated tax amount within two months after the end of the first six months of its accounting period. The prepaid tax is creditable against its annual tax liability.