On all purchase/sale of property in Thailand there is a stamp Duty of 0.5%, a transfer fee of 2%, a business tax of 3.3% levied against an owner who has been in registered possession of the property less than 5 years, and Income Tax.
Income Tax is typically between 1.0 – 3.0% on property based upon the Government appraisals, and Thailand does not have any Capital Gains Tax.
There are no set rules on who pays the income tax, so this is something that must be taken into consideration when bargaining terms of sale.