The ceremony will be held at the Soweto stadium, where Mandela made his last public appearance at the 2010 World Cup. Nearly 100 heads of state will be among the estimated 100,000 mourners expected at the stadium. A stage protected by bulletproof glass has been erected in preparation for the event.
The Obamas left Washington for Johannesburg aboard Air Force One on Monday. They were joined by former President George W. Bush, his wife Laura and former first lady Hillary Clinton. Former Presidents Bill Clinton and Jimmy Carter are traveling separately to South Africa.
Ahead of the stadium event, United Nations Secretary General Ban Ki-moon and retired Archbishop Desmond Tutu spoke at an event at the Nelson Mandela Centre of Memory Monday night.
"What a fantastic gift God gave to us in this Mandela, who quickly became an icon, a global icon of forgiveness, of generosity of spirit," Tutu said.
"He really was like a magician with a magic wand, turning us into this glorious, multi-colored, rainbow people," said Tutu.
Aside from Mr. Obama, United Nations Secretary-General Ban Ki-moon and Chinese Vice President Li Yuanchao, will also speak at the memorial. Others speakers include Brazilian President Dilma Rousseff, Namibian President Hifikepunye Pohamba, Indian President Pranab Mukherjee and Cuban President Raul Castro. South African President Jacob Zuma will give the keynote address.
The Associated Press contributed to this report.