Citizenship by birth
According to Chapter 2 of the 1995 law, anyone who was considered to be a "citizen by birth" prior to the enactment of the law or who is born in the Republic on or after the enactment of the law is a citizen by birth. Also, a person is a "citizen by birth" if they can be considered a citizen by descent and at the time of birth at least one parent was:
1) in the service of the government
2) was employed by a person or group located in the Republic
3) was in the service of an international organization in which South Africa had membership.
There is an exception to the birthright citizenship provision: those born to visiting foreign diplomats or their employees, or nonresident aliens are not considered to be "citizens by birth" (unless their other parent is a citizen, in which case they are a citizen by birth).
Citizenship by descent
Under the 1995 law, a person born outside South Africa to a South African parent is a South African citizen by descent upon registration of the birth under South African law.
Citizenship can be acquired through naturalisation if the following conditions are met:
• Valid residence permit or Certificate of Exemption;
• One year of ordinary residence in South Africa prior to the application for naturalisation;
• Four years of physical (actual) residence in South Africa during the eight years before the application for naturalisation, excluding the year of ordinary residence;
• In the case of an applicant for naturalisation being married in a spousal relationship with a South African citizen, two years of permanent residence and two years of marriage/spousal relationship to the South African citizen spouse prior to the application;
• Be of good and sound character;
• Be able to communicate in any one of South Africa's official languages satisfactorily;
• Have adequate knowledge of the duties and responsibilities of a South African citizen.
• Naturalisation of an adult also confers South African citizenship upon that adult's minor children.
Loss of citizenship by naturalised South Africans
Naturalised South Africans who left South Africa before 6 October 1988 and did not obtain a 'Letter of Exemption' from the South African authorities may have lost South African citizenship after seven years absence.
Prior to 2004, South Africa in principle did not recognise the multiple citizenship of its nationals unless the citizen applied for an exemption or permission letter under a 1995 law permitting South African citizens to travel using foreign passports.
Since 2004, South African dual nationals may travel without hindrance as long as they enter and leave South Africa on their South African passports. Dual nationals may petition for temporary, emergency or "permanent" South African passports for this purpose.
South African citizens under the age of eighteen years are exempt and do not require permission as long as they acquire the foreign citizenship before their eighteenth birthday. They automatically retain their South African citizenship for life unless; once they have reached the age of 18 and they then wish to acquire a further foreign citizenship. They will then have to apply for prior permission to retain their South African citizenship – failing to do so, they will automatically lose their South African citizenship.
Source: Adapted from Wikipedia and dha.gov.za