Anthony Albanese has been received by King Charles III in a royal audience at Balmoral Castle in Scotland.
Accompanied by his fiancee Jodie Haydon, Mr Albanese flew to the Lossiemouth Royal Air Force base, where they were greeted by Scottish bagpipers upon touching down on Saturday morning, local time.
Mr Albanese posted a picture with the monarch on social media, saying it was a honour to meet with him.
Mr Albanese's audience with King Charles came a day after meeting with United Kingdom Prime Minister Sir Keir Starmer, where he spoke about the rise of populism and the far right.
When asked about the rise of Nigel Farage's Reform UK right-wing populist party, Mr Albanese told reporters that "governments have to come up with solutions, not seek to divide people".
He said people in Australia were "concerned about elements of the far right rising in various countries".
"Our job is to make sure that people continue to have faith in the system," he said.
Mr Albanese's meeting with King Charles comes a week after the monarch stressed the importance of the trilateral AUKUS relationship between the UK, US and Australia while hosting United States President Donald Trump at a state banquet.
"Our AUKUS submarine partnership, with Australia, sets the benchmark for innovative and vital collaboration," the King said at Windsor Castle, as Mr Trump, seated next to him, nodded.
Mr Albanese will also speak at the British Labour Party conference in Liverpool, underscoring his close relationship with the progressive movement in the UK.
The prime minister's final stop before heading home will be in the United Arab Emirates, where he will meet President Sheikh Mohammed bin Zayed Al Nahyan.
There, the pair will discuss the two countries' free trade agreement, the Australia-UAE Comprehensive Economic Partnership.