While in the UK he will be joining Queen Elizabeth for lunch, but also making a long awaited intervention in the UK's EU referendum.
He's going to tell a town hall full of younger voters that the US, as "a friend", thinks the UK should remain in the EU.
Obama is likely to add that the UK's prosperity and influence would be diminished outside of the 28-member bloc.
The president will be speaking at Downing Street tomorrow afternoon.
Read more: It's crunch time for the European Union
Despite positive recent polling data for the Remain camp, Obama's intervention will come at the end of a difficult week for those backing continued membership, given the furore over the Treasury's intervention.
Yesterday Prime Minister David Cameron said: "I believe we should listen to advice and I struggle to find the leader of any friendly country who thinks we should leave."
A number of pro-Leave politicians have taken the issue seriously, warning the president off saying anything about the referendum.
Last week Mayor of London Boris Johnson said it would by hypocritical of the US to state support for the UK's membership in the EU, while Ukip leader Nigel Farage said Obama was the most anti-British president ever.
Some MPs had even previously written an open letter to the president to ask him to stay out of the debate, which has gone unheeded.
However, Remain campaigners say the Leave camp are acting hypocritically, pointing to the fact that Leave campaigners have previously praised foreign politicians for their views on Europe.
British voters, in contrast, believe that Obama should be able to speak his mind. Some 66 per cent said so in a YouGov poll last year.
While in the UK, Obama and Cameron are also set to discuss other high profile issues, including Syria and intelligence sharing.
And with the Queen's birthday, Obama's visit and the anniversary of Shakespeare's death, there could be a boost in tourism in store for the UK.
VisitBritain is hoping that the events put together could lead to an opportunity to showcase the best of Britain to the world.
"As the world’s media turns its attention to these significant events and to some of our most iconic sites including Windsor Castle, where President Obama will dine with Her Majesty The Queen and Stratford-upon-Avon as we mark the 400th anniversary of the Bard, we’ve got a fantastic opportunity to showcase Britain as truly the "home of amazing moments" with experiences that visitors – including the president – can only get here," said Joss Croft, marketing director of VisitBritain.