The body of Sultan, who died of colon cancer in New York on Saturday, was flown back to Riyadh on Monday. Hundreds of men, including Saudi King Abdullah, gathered on the airport runway to watch as the coffin was lowered into an ambulance and driven away.
Sultan's funeral will be held before the afternoon prayer in the conservative Islamic state and his body will then be taken away for burial.
Saudi Arabia, which dominates world oil markets and holds profound influence over Muslims through its guardianship of Islam's holiest sites in Mecca and Medina, faces turbulence in its neighbours and a confrontation with regional rival Iran.
King Abdullah appears set to appoint veteran Interior Minister Prince Nayef as crown prince and heir, but his choice of a defence minister to replace Sultan may signal how the conservative Islamic state manages the transition to its future leaders.
King Abdullah, Sultan and Nayef have run the country since the late King Fahd fell ill in 1995, but the monarch is in his late 80s and has spent three months abroad this year recovering from a back problem that again required surgery last week.
He remains firmly in control of the kingdom, but the focus will increasingly fall on Nayef and some younger princes.
Chief among them is Prince Salman, the Riyadh governor who is a full brother of Sultan and Nayef and is seen as next most important in a ruling family that has prized seniority since it was founded by King Abdulaziz Ibn Saud in 1932.
"This all points to the key role of Prince Salman, who sooner or later will move up to crown prince," said a former diplomat to Riyadh who wished to remain anonymous.
"He will be the one who really decides whether the succession will stay horizontal among the sons of Ibn Saud or go vertical to one of the grandsons."
If the enigmatic Nayef becomes crown prince, his character will shape for years to come the way Saudi Arabia tackles a host of challenges at a time of unprecedented change, both for the kingdom and the wider Middle East.
"Nayef had some time with Sultan's long illness to run himself in as crown prince and he has acted on behalf of the king," said another former diplomat. "He has become acquainted with authority across the board."
To Saudi liberals, Nayef represents the stern face of the conservative establishment: opposed to any moves towards democracy or women's rights, a supporter of the religious police and the veteran head of an Interior Ministry that locks up political activists without charge.
"I'm very worried that Prince Nayef will be the next crown prince," said a 47-year-old woman who did not give her name. "I fear that reform plans will not go forward if he takes power."
Nayef was quoted soon after the September 11, 2001 attacks on the United States as doubting that any of his compatriots had been involved when 15 of the 19 hijackers were in fact Saudis.
However, former diplomats, local journalists and royal family members who have dealt with him paint a softer portrait of a man at the centre of Saudi politics for over three decades.
"Many things are said about Prince Nayef, but I find him to be a very kind man with a foot on the ground by meeting people," said Khaled al-Maeena, editor at large of the Arab News daily in Jeddah. "He has the pulse of the nation."
Reforms enacted by King Abdullah have aimed to strengthen private sector growth and loosen the grip of conservative clerics on the education system and judiciary.
"I don't think the gloom and doom about Nayef is justified," said the former diplomat. "You have to realise that Saudi Arabia is run by a coalition. It's not an autocracy run by one man."
During the long illness of Sultan and absences of the king, Nayef stood in for his elder brothers, meeting world leaders and managing the kingdom's day-to-day affairs.
"I don't think there will be a substantial change of direction," said Hossein Shobokshi, a columnist for the state-owned news channel Al Arabiya. "The country has always opted for the non-surprising method. So we don't see any big decisions in policy."
People familiar with him also point out that, as interior minister, Nayef interacts with ordinary Saudis more frequently than any other senior prince, dealing with the problems of individual citizens in matters ranging from crime to poverty.