The later of the two departing overnight flights from South Africa to London will no longer be in operation from April 20.
Instead, the airline will operate the single flight departing Johannesburg early in the evening before setting off on the return leg from the UK.
SAA chief executive Vuyani Jarana said: “We have decided to focus on those areas of our business that will enhance our efficiencies, bring more value to our customers and produce improved overall performance of the airline.