Centre-left Moon suggested on the campaign trail that as president he would be willing to go to Pyongyang before Washington, but he is making the US his first foreign destination since he was sworn in last month after a landslide election win.
Washington is the South's security guarantor and has more than 28,000 troops in the country to defend it from its neighbour, which has been intensifying missile tests -- including five since Moon's inauguration -- as it seeks to develop nuclear-capable ballistic missiles that could reach the continental United States.
There have been misgivings about the first tete-a-tete between Moon and Trump, who is pushing for tougher sanctions against Pyongyang to curb its nuclear ambitions and whose administration has said military action was a possibility.
That would put Seoul on the front line of any retaliation from the North.
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But analysts say their first encounter is likely to be low on drama with the two getting a sense of each other, rather than displaying jarring differences.
"So there doesn't have to be a train wreck over North Korea policy," he told AFP.
Also high on the agenda is likely to be a controversial US missile defence system that has been installed in South Korea to guard against missile threats from the North.
Though parts of the Terminal High-Altitude Area Defense (THAAD) system are already in place, Moon suspended further deployment following a furious campaign of economic sanctions and diplomatic protests by Beijing against the US missile shield, dealing a blow to Washington's regional security policy.