Nicola Sturgeon has said the Prime Minister’s arrival in Scotland will boost the independence campaign.
Johnson touched down at Kirkwall Airport in Orkney just after 10am on Thursday.
Ahead of the visit, he hailed the “sheer might” of the UK Government, which he said had saved 900,000 Scottish jobs during the coronavirus pandemic.
The PM will visit businesses affected by lockdown, but has no plans to meet the First Minister during the trip.
Sturgeon tweeted that his presence showed how Scotland has “its future decided by politicians we didn’t vote for, taking us down a path we haven’t chosen”.
Johnson arrived in Scotland ahead of his one-year anniversary as Prime Minister on Friday.
It’s his first visit north of the border since the general election in December.
Ahead of the visit, the Prime Minister said: “When I stood on the steps of Downing Street one year ago, I pledged to be a Prime Minister for every corner of the United Kingdom.
“Whether you are from East Kilbride or Dumfries, Motherwell or Paisley, I promised to level up across Britain and close the opportunity gap.
“The last six months have shown exactly why the historic and heartfelt bond that ties the four nations of our country together is so important and the sheer might of our union has been proven once again.”
The Prime Minister’s visit comes after a surge in support for Scottish independence in recent months, according to polls, with two Panelbase surveys reporting 54% of respondents would like to see Scotland split from the UK.
The same polls predicted the SNP will win a majority of seats in the Scottish Parliament at next year’s election.
Then prime minister David Cameron agreed to stage the independence vote in 2014 after the SNP won a majority at Holyrood in the 2011 election, but Mr Johnson has repeatedly ruled out another referendum.
The Prime Minister praised the work of the armed forces in running mobile coronavirus testing centres in Scotland and providing air transfers support.
He added: “The UK Treasury stepped in to save the jobs of a third of Scotland’s entire workforce and kept the wolves at bay for tens of thousands of Scottish businesses.
“More than ever, this shows what we can achieve when we stand together, as one United Kingdom.”
Writing in The Times newspaper, he added that the coronavirus lockdown could have “spelled disaster for the country, an economic tsunami that washed away hundreds of thousands of Scottish jobs and saw countless businesses lost for ever below the waves”.
But he added: “It didn’t happen. Instead the Scotland I’m visiting today is a nation where a third of workers have had their jobs protected rather than being made redundant.
“Where shops, factories, pubs and more have still been there to return to as the lockdown eases. And where much needed wages were paid in communities across the country even as the doors of workplaces remained firmly bolted.”
Johnson said that showed the “power of our Union”, stating this was “only going to get more important as the world sails nervously into economic waters made alarmingly choppy by this unprecedented pandemic”.
The PM continued: “That doesn’t mean we should dismiss the Union as simply a lifeboat to which our four nations can cling in times of peril.
“Because our true strength is revealed not by our ability to weather storms but in the way that, since 1707, we time and again have bounced back from adversity and moved forwards together.
“And we will recover together once again now.”