Prince William and Princess Kate of Wales greeted Ramaphosa at his London hotel, then escorted him to the welcome ceremony on Horse Guards Parade near Buckingham Palace
The last state visit by a South African leader was in 1996, when Nelson Mandela was honored two years after he became South Africa's first Black president.
Ramaphosa addressed a joint session of the U.K. Parliament on Tuesday, urging U.K. Prime Minister Rishi Sunak to triple the number of South Africans studying in the U.K. to build business ties.
He spoke in Parliament's Royal Gallery, becoming the first South African president to address lawmakers since Mandela in 1996.
On the agenda are opportunities for British companies to take part in up to 5.4 billion pounds ($6.4 billion) of infrastructure projects over the three years
Aside from meeting the royals, the South African head of state will also visit Westminster Abbey where he will lay a wreath at the Tomb of the Unknown Warrior and see the memorial stone for Nelson Mandela.