Singapore’s foreign minister Vivian Balakrishnan announced the arrival by posting a picture on Twitter of him shaking hands with Mr Kim wearing glasses and a dark Maoist suit.
“Welcomed chairman Kim Jong Un, who has just arrived in Singapore,” he said.
The scheduled meeting on the island of Sentosa on Tuesday is set to be the first time the leaders of the US and North Korea have met. They have never even spoken on the phone before.
The two countries were on the brink of war last year, with their leaders trading insults and threats, until Mr Kim made a dramatic offer in March to meet Mr Trump and discuss nuclear disarmament, which the American president quickly accepted.
Mr Kim’s journey from international pariah to being regarded as a responsible head of state has taken just a few months.
After inheriting an intermittent nuclear programme that was making little progress, Mr Kim poured his countries scarce resources into developing a nuclear-armed missile capable of hitting the United States.
North Korea announced it had achieved that capability late last year. Although unproven, the claim was credible enough for Washington to take Mr Kim more seriously.
On Thursday, Mr Trump dangled the prospect of normalised relations with the United States, and even a White House visit for Mr Kim if he ditched his nuclear arsenal.
For Mr Kim, who is third in North Korea’s ruling dynasty, the summit affords both him and his long-isolated country the international legitimacy of which his father and grandfather could only dream.
Mr Trump said he and Mr Kim could even sign an agreement to end the Korean War, which was concluded only with a truce, not a peace treaty.
Reuters contributed to this report