President Barack Obama is heading for Robben Island in Cape Town, where Nelson Mandela was jailed for 18 of his 27 years' imprisonment under white apartheid rule.
Sunday's trip is part of the US leader's three-nation Africa tour, which a day earlier saw him meet with South Africa President Jacob Zuma and members of Mandela's family.
Obama will also build the keynote speech of his tour at the University of Cape Town around Mandela, and will cite his unifying legacy of a blueprint for a new generation in emerging Africa.
A visit to an AIDS clinic with Desmond Tutu, the retired Archbishop of Cape Town who received the Nobel Peace Prize in 1984, is also on the agenda.
Elsewhere, the Reuters news agency reported that Sunday will see the announcement of a $7bn initiative over five years to double access to power in sub-Saharan Africa.
"We see this as the next phase in our development strategy and a real focal point in the president's agenda going forward," Ben Rhodes, deputy national security adviser, told reporters.
Speaking a day earlier in Pretoria, just a few miles away from the hospital where Mandela is being treated, Obama said:"For me to be able to bring my daughters there and teach them the history of that place [Robben Island] and this country ... that's a great privilege and a great honour."
Tricky trip
Mandela's illness has placed Obama in a tricky political spot, forcing him to balance his desire to push for a new economic relationship with Africa, with the need to properly honour his hero as the world braces for his passing.
On Saturday, Obama and his wife Michelle phoned Mandela's wife Graca Machel.
"I expressed my hope that Madiba draws peace and comfort from the time that he is spending with loved ones," Obama said in a statement using the 94-year-old Mandela's clan name.
Machel said she drew "strength from the support" from the Obama family.
The example of Mandela, South Africa's first black president, drew Obama into politics for the first time in the 1970s, putting him on a path that would make his own piece of history as America's first black president.
"The struggle here against apartheid, for freedom, Madiba's moral courage, his country's historic transition to a free and democratic nation, has been a personal inspiration to me," Obama said.
'Nobama'
But Obama's warm welcome has not been universal. Anti-Obama protesters in the township of Soweto, once a flashpoint in the anti-apartheid struggle, tried to stage a demonstration prompting police to fire one stun grenade at the crowd.
Under the group name 'Nobama', some of those against the president's visit are also expected at events on Sunday.
Many Soweto residents, however, see Obama, the son of a white American mother and a Kenyan father, as a "fellow African".
"To me, Madiba represents an older and perhaps more traditional generation of black leaders, while Obama represents the new generation," said Tshepo Mofokeng, 43. "I'm sure he will be welcomed here as an African."
Not far from the protest, Obama held a town hall style meeting with 600 young African leaders with a video link up to young people in Nigeria, Uganda and Kenya.
Africa "is in your hands" Obama told the youngsters and urged them to use Mandela as a model for political leadership.
"Think about 27 years in prison ... there were dark moments that tested his faith in humanity, but he refused to give up."
Obama's tour of Senegal, South Africa and Tanzania is aimed at changing perceptions that he has neglected Africa since his election in 2008, while also countering China's growing economic influence in the resource-rich continent.
