The couple’s children, Prince Archie, seven, and Princess Lilibet, five, are enrolled to start at a British school in September.
King Charles was told of the move on Sunday. There are no current plans for either Prince Harry or Meghan to resume their roles as working royals.
The Sussexes left the UK and stepped back from their royal duties in early 2020, before settling in California in March that year.
They were last in the UK in July to visit the King and Queen Camilla, in what was seen as a key development in their relationship.
The Palace described the meeting at the King’s private home in Gloucestershire as a “private family occasion”.
It was the first time the King had seen his grandchildren in person in more than four years, and the couple’s first visit to the UK together since 2022.
It is understood that July’s visit had to be adjusted after the duke’s request for police protection was rejected.
Last year, Prince Harry lost a legal challenge in which he sought to overturn a decision that had downgraded his security after his move to the US.
At the time, he told the BBC that he “can’t see a world” in which he would bring his family to the UK due to the downgrading of his protection.
It is unclear what provisions will be made for their security once they return to the UK.
Royal expert Robert Hardman told the BBC’s Radio 4 Today programme it was likely that some of their past security issues “have been resolved” but details – or who is going to foot the bill – are still unknown.
The children’s enrolment in school indicated a “clear direction of travel”, Hardman said, adding that the children are now going to be raised as “British rather than American”.
In the US, the Sussexes have employed a private security team to protect them.
They offered no comment when asked by the BBC whether that team would be moving to the UK with them.
