Trump is the only American president to visit Saudi Arabia, or any Muslim-majority country. His aim is to show respect to the region after months of harsh anti-Muslim rhetoric that has surrounded his administration.
Trump flew to Riyadh overnight on Air Force One. He was greeted at the airport with an elaborate ceremony, punctuated by a military flyover and a handshake from Saudi King Salman.
Melania Trump wore a black pantsuit with a golden belt and did not cover her head for the arrival, consistent with custom for foreign dignitaries visiting Saudi Arabia. In 2015, her husband had, in a tweet, criticized former first lady Michelle Obama for not wearing a headscarf during a visit to the kingdom.
The president's stop in Saudi Arabia kicks off an ambitious international debut. After two days of meetings in Riyadh, Trump will travel to Israel, have an audience with Pope Francis at the Vatican, and meet with allies at a NATO summit in Brussels and the Group of 7 wealthy nations in Sicily.
As he arrived, the president waved from the doorway of Air Force One and then descended the steps, joined by the first lady.
The 81-year-old king, who uses a cane for support, was brought to the steps of the plane on a golf cart. The two leaders exchanged pleasantries and Trump said it was "a great honor" to be there.
Several jets then flew overhead leaving a red, white and blue trail.
Saudi Arabia offered Trump the elaborate welcome ahead of his two-day stay. Billboards featuring images of Trump and the king dotted the highways of Riyadh, emblazoned with the motto "Together we prevail."
Trump's luxury hotel was bathed in red, white and blue lights and, at times, an image of the president's face.
Trump and the king met briefly in the airport terminal for a coffee ceremony before the president headed to his hotel before the day's other meetings.
White House Chief of Staff Reince Priebus told reporters on Air Force One that Trump spent the flight meeting with staff, working on his upcoming speech to the Muslim world and getting a little sleep.
White House officials hope the trip gives Trump the opportunity to recalibrate after one of the most difficult stretches of his young presidency. The White House badly bungled the president's stunning firing of FBI Director James Comey, who was overseeing the federal investigation into possible ties between Trump's campaign and Russia. On Wednesday, the Justice Department relented to calls from Democrats to name a special counsel, tapping former FBI chief Robert Mueller to lead the probe.
In a sweetener for Saudi Arabia, U.S. officials said the Trump administration plans to announce $110 billion in advanced military equipment sales and training to the kingdom during the trip. The package includes tanks, combat ships, missile defense systems, radar and communications and cybersecurity technology.
After spending much of Saturday meeting with King Salman and other members of the royal family, Trump was to end the day at a banquet dinner at the Murabba Palace. On Sunday, he'll hold meetings with more than 50 Arab and Muslim leaders converging on Riyadh for a regional summit focused largely on combating the Islamic State and other extremist groups.
Trump dodged one potential land mine when Sudanese President Omar al-Bashir, who has been indicted on war crime and genocide charges, announced that he would not attend the summit for personal reasons.
The centerpiece of Trump's visit to Saudi Arabia will be a speech Sunday at the Arab-Islamic-American summit. White House aides view the address as a counter to Obama's 2009 speech to the Muslim world, which Trump criticized as too apologetic for U.S. actions in the region.
Trump will call for unity in the fight against radicalism in the Muslim world, casting the challenge as a "battle between good and evil" and urging Arab leaders to "drive out the terrorists from your places of worship," according to a draft of the speech obtained by The Associated Press. The draft notably refrains from mentioning democracy and human rights — topics Arab leaders often view as U.S. moralizing — in favor of the more limited goals of peace and stability.
It also abandons some of the harsh anti-Muslim rhetoric that defined Trump's presidential campaign and does not contain the words "radical Islamic terror," a phrase Trump repeatedly criticized Hillary Clinton for not using during last year's campaign.