Air Force One touched down at 10.15 pm (2015 GMT), kicking off Trump's second foreign trip.
Looming large over the entire visit is Pyongyang's test of a intercontinental ballistic missile that could deliver a nuclear payload to Alaska, a brazen threat to US security.
Tough-talking Trump had previously declared that technological step a red line, and leaders from rival and allied powers alike will be watching closely to see whether his threats were bluster, or a harbinger of action to come.
After trying and failing to convince Beijing to ratchet up the pressure on North Korea, Trump will hold what promises to be a testy meeting with Chinese President Xi Jinping in Hamburg to trace the next steps.
"Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us - but we had to give it a try!" Trump tweeted indignantly on Wednesday.
On Friday, Trump will hold a full bilateral meeting with Putin that is laden with US domestic political overtones and will be pored over for years to come.
Several of Trump's closest aides are under investigation for possible ties with Moscow, which US intelligence agencies say tried to tilt the election in the Republican candidate's favour.
The scandal continues to eat away at his adminstration, with key White House staff being forced to hire their own lawyers and spend precious time rebuffing new allegations.
So far, Trump has been reluctant to acknowledge Russian interference in the election or criticise the veteran Russian leader.
Even simple photographs of Putin and Trump shaking hands or meeting face-to-face pose a political risk for the US president and would surely be weaponised in attack ads by his foes in the United States.
'Disastrous trip to Brussels'
Trump's first trip to Europe last May exposed fierce mistrust across the Atlantic, so in some ways this will be a do-over.
In Poland, Trump will have a willing host in the form of President Andrzej Duda, whose own rightwing politics resembles "The Donald's" in many ways.
Trump will look to a public speech on Thursday to burnish his credentials as a global statesman and deflect allegations that he has invited ridicule on the United States.
"After his disastrous trip to Brussels and Taormina, friendly pictures with European leaders and cheering crowds at his public speech could help Trump repair his image at home," said Piotr Buras of the European Council on Foreign Relations.
In public, European officials profess the decades-old transatlantic partnership to be inviolable and essential.
In private, they wonder whether it can survive four or eight years with Trump at the helm.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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