Many see his attendance at the Group of Seven summit and then the NATO summit over the next week as a one-shot chance: not just to help fix relations with Washington's bruised allies, but also to reassert the faltering influence of the U.S. and the West itself.
The visit will also be shadowed by questions about whether Biden, for all his trans-Atlantic experience, is actually more focused on the rising competitor in Beijing than in old Cold War allies across the pond.
"After four tumultuous years of Trump, the Europeans have now got the U.S. leadership they always dreamed of," said Fabrice Pothier, NATO's former head of policy planning. "Except now the story has moved on."
From Friday to Sunday, Biden and his team will attend the G-7 summit of the leading industrial nations, an international spectacle crammed into the small Cornish seaside resort of Carbis Bay, in the southwest corner of England.
On Monday, he will travel to Brussels for a brief NATO summit before he flies to Geneva for a face-to-face meeting with Russian President Vladimir Putin on Wednesday.
The meeting with Putin is likely to involve strong words. But the G-7 is where decisions that will shape U.S. international relations and the world will or won't be made.
The G-7 is a club of industrialized postwar allies — the U.S., Canada, the U.K., Germany, France, Italy and Japan — that first met in 1975. Russia joined in 1997, making it the G-8, before it was kicked out in 2014 for invading Ukraine's Crimea peninsula.
This year there are four guest countries: India, Australia, South Korea and South Africa.
On the agenda are the global coronavirus response, climate change, trade and technology. But Biden has made it clear that he sees the trip more broadly as an opportunity to rally allies behind the cause of liberal democracy in what he considers to be a struggle against the authoritarianism of Chinese President Xi Jinping, a characterization Beijing rejects.
The White House says the most immediate way to do that is through the global coronavirus response — to provide "a high-standard, climate-friendly, transparent and rules-based alternative to what China is offering," as national security adviser Jake Sullivan put it in a briefing Monday.
The past year has hardly been an ad for the West, as the U.S. and others failed to stop mass Covid-19 deaths and then distributed vaccines only domestically before agreeing to donate them to poorer countries.
Meanwhile, China has controlled the virus within its borders, its economy is booming this year, and it has sought to improve its image abroad by donating or selling tens of millions of vaccine doses.
If this is, indeed, an inflection point for the West, it comes soon after many experts wondered whether the G-7 had become obsolete. Then-President Donald Trump wasn't alone last year when he called it "a very outdated group of countries"; critics have said it is a Cold War relic ill-suited to dealing with the complex problems of the modern world.
"The world is waiting to see whether the G-7 can lead the world out of this crisis in a way that's productive," said Leslie Vinjamuri, director of the U.S. and the Americas program at Chatham House, a London think tank.
"Will the West stand up and lead and, quite frankly, get shots in the arms of all those people across the rest of the world who desperately need it?" she asked. "If they don't get it from the United States and from Europe, they're going to look to China and they're going to look to Russia."
Global opinion of the U.S. nosedived in most countries during Trump's presidency — particularly among Washington's traditional allies — according to regular surveys by the Pew Research Center, a Washington think tank.
Since Biden was elected, there has been "a dramatic shift in America's international image," Pew said Thursday, with public opinion of both Biden and the U.S. rebounding in a dozen key countries since he took office.
Most European leaders are doubtless relieved to see the back of Trump and his caustic approach, and they have welcomed Biden's enthusiastic multilateralism. But they will still be wary. A big reason is that Europe's powers appear more reluctant than Biden to take a hard line on China.
The European Union halted a huge investment deal with Beijing in response to allegations of human rights abuses in the western province of Xinjiang, which China denies. But many see the confrontational approach of "all together against China" as "counterproductive," French President Emmanuel Macron said in a speech in February.
Even though the investment deal was paused, economic ties run deep. China remains Germany's largest export market, for example.
Some European officials are also cautious about throwing their weight behind Biden when they fear he could be easily replaced by Trump, or someone like him, in 2024.
Others question whether Biden's democratic call to arms is a friendly invitation or more a directive with strings attached.
Europe's economic clout has faded in recent years as the G-7's share of the global economy has plummeted from 80 percent when it was founded to 40 percent today. Many experts here say Europe is becoming ever more the junior partner in the trans-Atlantic relationship.
Some saw evidence of this imbalance when, with little warning, Biden backed waiving intellectual property rights for vaccines this year. It was awkward when German Chancellor Angela Merkel came out against the move.
European experts know that "the U.S.'s strategic focus is not on Europe at all — it's on the bigger, much more complicated game going on with China," said Pothier, who is now a consulting senior fellow at the International Institute for Strategic Studies, a London think tank.
Covid-19 looms large
"I think it's no exaggeration to say that Friday's G-7 is a life-and-death matter," former British Prime Minister Gordon Brown said this week at an event hosted by Chatham House. "Its decision will determine who is vaccinated and safe and who remains unvaccinated and at risk of dying."
Having vaccinated large chunks of their own populations, Biden and some of his allies have promised to start donating millions of doses abroad.
Brown is among those who fear that, while the G-7 is likely to make progress on vaccine donations, it won't go far enough, allowing China and Russia to vigorously promote their policy of vaccine diplomacy.
"After a year when international cooperation failed dismally, we are at a turning point — where history may turn, or it may not," Brown said.