Then, in 2018 he embarked on a 15-month international travel spree, heading to China, Russia, Vietnam and Singapore to meet world leaders, including then-US president Donald Trump, in a bout of ill-fated diplomatic engagement.

Talks collapsed and then the coronavirus pandemic hit, so Kim stopped travelling entirely, sealing off his country's borders for three years with even North Korean nationals not allowed to return.

But he embarked this week on his first overseas trip since 2019, heading by train to Russia.

AFP looks at all of Kim's previous international trips:

- China, March 2018

Kim's first overseas trip as leader was to Beijing in March 2018, travelling overland in his bullet-proof train to meet President Xi Jinping

He told Xi there was "no question that my first foreign visit would be to the Chinese capital".

The meeting came after China had supported a series of tough UN resolutions imposing sanctions on Pyongyang after Kim ramped up nuclear and ballistic missile testing.

- China again, May 2018

Kim was back in China just months after his first visit, this time flying to the eastern port city of Dalian.

He met Xi again and the timing, just ahead of Kim's first meeting with Trump, sparked speculation China was seeking to discuss a possible Pyongyang-Washington rapprochement.

- South Korea, May 2018

Kim met then-South Korean president Moon Jae-in on May 26 for talks at Panmunjom, on the demilitarised zone between the two countries.

He spent several hours on the southern side of the border, meeting Moon for dinner and talks.

- Singapore, June 2018

Kim arrived in Singapore on June 10 on an Air China 747 plane provided by Beijing for a historic first summit between North Korea and the United States.

Kim met Trump two days later and signed a declaration pledging to "work toward the complete denuclearisation of the Korean Peninsula", but with no timeline.

In return, Trump said he would stop joint military drills with South Korea, long seen as a provocation by Pyongyang and Beijing.

- Third China trip, June 2018

Kim was back in China a week after the Singapore summit, flying to Beijing to see Xi.

They exchanged vows of friendship and promises of economic cooperation in a carefully choreographed display of amity.

The summit was largely seen by experts at the time as Kim briefing Xi on the Singapore summit.

- Fourth China trip, January 2019

Kim made his fourth trip to China, again travelling on his armoured train, to meet Xi.

Xi visited Pyongyang five months later, the first visit by a Chinese leader to North Korea since 2005.

He offered Kim Beijing's firm backing in deadlocked nuclear talks with the United States.

- Vietnam, February 2019

Kim arrived in Hanoi after more than 60 hours on his bullet-proof train, having travelled overland from Pyongyang.

But the second Trump-Kim summit on February 28 collapsed dramatically, with the two sides failing to agree on the specifics of the denuclearisation measures the North would take in exchange for sanctions relief.

- First Russia trip, April 2019

Kim crossed the border into Russia on his heavily armoured train and held his first summit with President Vladimir Putin in the eastern city of Vladivostok on April 25, 2019.

He blamed Washington for the botched Hanoi summit, accusing the United States of acting in "bad faith".

- South Korea, briefly, June 2019

After the collapse of the Hanoi summit, Trump made a flying visit to Seoul and went to the DMZ to meet Kim at the border.

Trump became the first US president since the Korean War to step into the North, briefly crossing the low concrete divide that marks the border at Panmunjom. Kim also crossed into the South's territory.

- Russia again, September 2023

Kim's train has trundled across the border, with North Korea's leader set for another summit with Putin. This time it is likely to focus on arms deals and military cooperation following Moscow's invasion of Ukraine.