South Africa only became a unified country in 1910. Before that there was the Cape Colony, Natal, Orange Free State and Transvaal.
In the Cape Colony all men, regardless of race, were allowed to vote by virtue of the 1853 Constitution, provided he owned property or had enough money – £25. In 1887 Cecil John Rhodes and Gordon Sprigg enacted legislation to curb the voting rights of non-white citizens, especially in the Eastern Cape. In 1872 a non-racial franchise was implemented by the Cape Franchise and Ballot Act, still only for men, but with the £25 franchise qualification raised to £75 and an educational qualification requiring all voters to be literate.
In the Transvaal and the Orange Free State only white men had voting rights.
In Natal nearly all black Africans were effectively excluded from the franchise.
In 1910 the four colonies became the Union of South Africa but the voting situation stayed the same in the provinces as it had been before the Union.
White women over the age of 21 were given the right to vote in 1930 (together with the right to stand for election). Neither the property nor the education qualifications for voting applied to women.
In 1931 the Franchise Law Amendment Act changed so that all white men and white women were enfranchised without qualifications.Qualifications however still applied to non-white voters in the Cape Province and Natal.
In 1936 Hertzog did away with the common voter’s roll, placing black men on a separate voter’s roll. In the fifties and sixties the Nationalist government began the process of disenfranchising black and coloured citizens, a process which eventually resulted in the formation of a Tricameral Parliament in 1983 in which black South Africans could vote for black local government structure.
In 1994, the Interim Constitution gave all South Africans irrespective of race and gender of the age 18 and over the right to vote. The 1996 Constitution called for “a national common voters roll, regular elections and a multi-party system of democratic government”.
So, today, 3 August 2016, all South Africans over the age of 18 should go and vote.