Mark Shuttleworth has been learning Russian
The 28 year old is reported to have paid $20m (£14m) for the trip which is due to blast off on Thursday.
He also spent five days at the US space agency's (Nasa) Johnson space center.
Mr Shuttleworth made his fortune as an internet entrepreneur. He set up a security business at the age of 22 from his parent's garage in Cape Town. He sold the company four years later for $400m (£280m).
Learning Russian
Mr Shuttleworth is using the money to fulfil the dream of becoming the first African in space. He was inspired by Dennis Tito's trip last April.
But he has faced criticism at home for spending so much money on a personal adventure.
He has deflected anger by launching a schools campaign to promote science and maths.
His education foundation, The Shuttleworth Foundation, is creating software to help schools in developing countries.
Dreaming of space
Mr Shuttleworth says he is learning Russian and can follow 70% of the cockpit conversation between mission commander Yuri Gidzenko and the ground crew.
He also plans to carry out Aids research in space.
"Each of us has a dream, a desire, something we want to fulfil in life," Mr Shuttleworth, clad in a blue jumpsuit adorned with the South African flag, said during a preflight media conference.
"I had always hoped and believed that I would fly into space but I had always thought I would have to wait until the day when I could fly as a passenger.
"I believe we are just scratching the surface of space - in the next few years we will not only explore it more deeply, but make the cosmos more accessible."