Profits from the sale of property is not taxable as it is a capital gain. But if a person is deemed to be trading in properties, gains from the sale become income and are taxable.
Criteria to determine whether tax is due include frequency of transactions, reasons for acquiring and selling property and holding period.
For non-residents in Singapore, net rental income will be taxed at the prevailing non-resident rate of 20 per cent.
Source: Inland Revenue of Singapore