Trump, landing in darkness, waved as he disembarked Air Force One and was met by senior Vietnamese and USA officials.
The White House offered no explanation for the move, which forced news organisations operating from the hotel to pack up and relocate several streets away.
"We saw the leader from afar". Kim said: "I am certain that a great outcome will be achieved this time that will be welcomed by all people".
Dongguk University professor Koh Yu-hwan said the nuclear deadlock arose mainly from North Korea's misinterpretation of the Singapore agreement.
However, the meeting did not explicitly define denuclearisation - leading to disagreements over what it means - nor did it detail a specific timeline for the destruction of North Korea's nuclear weapons arsenal.
Kim Yo Jong can be seen carrying an ashtray for him.
Trump did not answer a question from a reporter about his former attorney Michael Cohen's congressional testimony.
That might not be of particular concern to Mr Trump, who has openly questioned the cost of the large USA troop presence and recently forced the negotiation of a new cost-sharing agreement with South Korea.
After arriving at the China-Vietnam border, Kim switched to a motorcade and drove the last 105 miles to Hanoi.
Before their first summit in June, there was a lot of talk about what denuclearization would look like. But in this case, it appears the change did not start to take place until after the House oversight committee announced on the afternoon of February 20 that Cohen would appear in open session.
Trump was taking a more conventional route on Air Force One to the meeting and was expected to arrive in Hanoi late on Tuesday. Yun added that Trump probably wants to continue meeting with Kim.
There is now a concern that a repeat of vague results will not be taken well this time around. If Trump is making progress toward peace, the Republican Senate will likely endorse it.
Kim and Trump shook hands and smiled briefly in front of a row of their national flags at the Metropole hotel in the Vietnamese capital, Hanoi, before heading to dinner together.
Trump faults previous administrations for inaction on North Korea. Robert Carlin, a visiting scholar and North Korea expert at Stanford University, calls the armistice "creaky" - akin to a 1957 Chevrolet still rumbling down the roads of Cuba.
Just as Trump's earlier unilateral cancellation of joint U.S.
Speaking to Sputnik's Loud and Clear, radio host Brian Becker noted that North Korea wants a guarantee that the USA will not engage in future nuclear intimidation tactics, while Washington has its own goal: denuclearization.
Kazianis said a political declaration that ended the war would be a win for both sides.
Mr Trump will greet Vietnamese President Nguyen Phu Trong and have a working lunch with Vietnamese Prime Minister Nguyen Xuan Phuc today, according to the White House. "It's yours if you'll seize the moment", Pompeo reportedly said.