If you are a foreign national with good credentials and have been in South Africa long enough, you can apply for naturalisation. Naturalisation is the acquisition of citizenship by somebody who is not a South African citizen by birth or descent. It is a process that a foreign national would have to go through to become a South African citizen.
Anyone with a South African permanent residence permit/certificate of exemption qualifies to apply for South African citizenship through naturalisation after five years of being a permanent resident holder. If you are married to a South African citizen for two years after you acquired permanent residence, you also qualify for naturalisation subject to the condition/s of the permanent residence permit. A child under the age of 18 years who has permanent residence permit qualifies for naturalisation immediately after the permit is issued.
Anyone who intends to apply for a citizenship anywhere in sub-Saharan Africa needs to check with his or her embassy first, if the application is not automatically revoking the existing citizenship. For Austrian and German nationals this is the case, but may be overcome through a special process allowing the retrospective acquisition of a second citizenship. The document proving this permission is called “Beibehaltungsurkunde” and INTO SA advises on the procedures to obtain such a certificate.