According to Hello! magazine, it will be held at Gatcombe Park.
The estate is owned by Princess Anne, who resides in the main manor house with her husband, Sir Timothy Laurence.
It is said to carry a “special resonance” for Peter, as it was also his childhood home.
Saturday’s nuptials will be the second time both Peter and Harriet are getting married.
Princess Anne’s son was previously married to Autumn Kelly from 2008 to 2021. Meanwhile, Harriet was married to Antonio St. John Sperling.
The couple’s spokesperson previously said when announcing their wedding: “Mr Peter Phillips, the son of HRH The Princess Royal and Captain Mark Phillips and Ms Harriet Sperling, daughter of the late Mr Rupert Sanders and Mrs Mary Sanders of Gloucestershire, have today announced their wedding date.
“The summer wedding will take place at All Saints Church, Kemble, Cirencester on Saturday 6th June 2026 in a private ceremony.
“Both families have been informed jointly of the wedding date by invitation.
“Their Majesties The King and Queen, The Prince and Princess of Wales have also been informed of the announcement. Further details will be announced in due course.”
Several members of the Royal Family are expected to attend the private family affair.