If you are already registered as a taxpayer, you will simply declare your capital gains and losses in your return of income covering the relevant year of assessment. Keep the records necessary to determine a capital gain or loss in a safe place as many years may elapse between the time you acquired an asset and the time you dispose of it.
 
If you are not registered as a taxpayer, you may have to do so depending on the extent of the capital gain. Consult the Annual Notice to  furnish returns issued by SARS to determine whether you need to register.
 

Buying immovable property from a non-resident seller
If you are buying South African immovable property from a non-resident seller you must complete form NR02 and an IRP6(3) using the seller’s income tax reference number and withhold the tax at the rate prescribed in section 35A(1) of the Income Tax Act, 1962 . You may withhold at a lower rate of tax if the seller supplies you with a tax directive from SARS authorising you to withhold at a lower rate. You must then submit the NR02 and IRP6(3) together with your payment to SARS. If the seller is not registered for income tax, the NR02 and offer to purchase must be forwarded to nres@sars.gov.za so that the seller can be registered for income tax before payment is due.
 
A non-resident seller of immovable property may be entitled to request that tax be withheld at a lower or even zero rate under section 35A(2) of the act. The reasons why a sale would attract a lower rate of CGT will depend on the facts of the particular case, for example, the person may be fully exempt from CGT, or in the case of an individual, have a low level of taxable income or have disposed of the property at a loss. To request a tax directive you must complete form NR03 and submit it together with the offer to purchase, tax calculations and supporting documentation to nres@sars.gov.za or use one of the other submission methods described on the form.