A heavily-guarded motorcade, believed to be Kim's, was filmed traveling from Changi to St. Regis Hotel, a 5-star property located in downtown Singapore.
Trump and Kim will meet on Tuesday at 9 a.m. for talks on denuclearization.
"As the venue and time of the summit have already been announced, security for Kim Jong Un will be tighter than for any other VIPs", said the professor, who was the first academic to establish a university major in South Korea on guarding and protection.
In addition to protection, the North Korean delegation may fine-tune its security detail to project a particular image for Kim Jong Un, said Ahn Chan-il, a defector and current president of the World Institute for North Korea Studies.
But North Korea's closest ally, China, has not been invited to take part in the Singapore summit.
Singapore Prime Minister Lee Hsien Loong will be meeting Kim later on Sunday, according to the Ministry of Foreign Affairs.
The U.S. administration officials included on the trip are Secretary of State Mike Pompeo, Chief of Staff John Kelly, National Security Adviser John Bolton, Deputy Chief of Staff Joe Hagin, Deputy National Security Adviser Mira Ricardel, National Security Council-Asia Director Matt Pottinger, senior adviser Steven Miller, press secretary Sarah Sanders and NSC communications official Sarah Tinsley. Any deal would likely depend on North Korea's willingness to open its facilities for inspection.
But since taking power in 2011 on his father's death, the youthful Kim has displayed a mixture of ruthlessness, pragmatism and statecraft to get this prize - to sit across the table with the leader of the United States and be treated as an equal.
Melania Trump Resurfaces After She Went "Missing" For 24 Days
Melania Trump , 47, attended a Hurricane briefing at the Federal Emergency Management Agency Headquarters (FEDA) on Wednesday. During her recovery from surgery they reported everything from near death, to facelift, to left the W.H.
In a New Year's address, Kim said his country had completed development of its nuclear programme and would focus on economic development, suggesting a meeting with South Korea.
"North Korea stands to be plugged into the rest of the world".
After a flurry of contacts between the two Koreas, South Korean officials suggested to Trump in March that Kim would be willing to meet face-to-face.
"In the last few years, it's been building nuclear weapons". It also successfully tested missiles that had enough range to reach the USA mainland.
Kim's journey from global pariah to being regarded as a responsible head of state has taken just a few months.
Trump is far less predictable, but badly needs the kudos that a successful summit will bring ahead of congressional elections in November.
The historic meeting will be the first time a North Korean leader meets a sitting United States president and will take place on Sentosa island on Tuesday.
Trump is expected to arrive sometime around 8 p.m. local time.