Apartheid as a formal government policy in South Africa started in 1948 when the National Party came to power and officially adopted the term and system of “apartheid” (“apartness”) for its racial segregation program.

However, to be fully accurate:

  • Racial segregation and discrimination against Black South Africans and other non‑white groups existed long before 1948, rooted in centuries of Dutch and British colonial rule.
  • What changed in 1948 was that the National Party turned these practices into a comprehensive, named system of laws and policies—this is what historians usually mean when they say “when did apartheid start.”

So, if someone asks “when did apartheid start,” the standard historical answer is: in 1948, with the National Party government’s formal introduction of the apartheid system.