The White House said travel arrangements were still being made and it was unclear when the Obamas and Bushes would depart. A memorial service for Mandela will be held Tuesday at a stadium in Johannesburg, followed by a smaller funeral on Dec. 15 in Mandela's hometown.
Former President Bill Clinton said he also planned to travel to South Africa, along with his wife, former Secretary of State Hillary Clinton. It was unclear whether the Clintons would also fly on Air Force One.
"My whole family will be there,'' Clinton said in an interview with CNN. "And we're looking forward to having the chance to say good-bye one last time.''
Mandela's death has sparked an outpouring of memorials and celebrations of the former prisoner turned president who led his country out of apartheid rule. In remarks following Mandela's death, Obama counted himself as one of the countless millions inspired by the South African leader.
"Like so many around the globe, I cannot fully imagine my own life without the example that Nelson Mandela set,'' Obama said Thursday.
The president spoke Friday with Mandela's widow, Graca Machel, and expressed condolences for the loss of her husband, both from his family and from the American people, the White House said.
For Obama and Bush, the trip to South Africa will mark the second time they have been on the continent together this year. The two men were in Tanzania at the same time this summer, though on separately planned trips.
They held a brief event together to honor victims of the 1998 U.S. Embassy bombing in Dar es Salaam. Mrs. Obama and Mrs. Bush both also attended an African first ladies summit during the trip.
Obama also invited 89-year-old former President George H.W. Bush to travel with him to South Africa, but a spokesman for the elder Bush said he would not be able to make the trip.
"He appreciates the kind invitation that he's received from the president and regrets that he'll be unable to attend,'' spokesman Jim McGrath said. "He's not able to travel those long distances any more, but he'll be with them in spirit.''
It was unclear whether Jimmy Carter, the only other living American president, would travel to South Africa.