The Prince wore a long brown coat over a suit and tie and brown shoes and could be seen carrying a black umbrella as he walked, accompanied by an aide.
It appears that the 73-year-old spent the weekend at the Norfolk estate, where he has had more involvement over the last five years.
Charles took over the running of Sandringham back in 2017, with a view to turning the farm into a fully organic operation.
WATCH: Prince Charles and Camilla arrive at Prince Philip's Service of Thanksgiving
He has increasingly implemented more sustainable processes during that time. It's been a busy week for the father-of-two, who attended the Duke of Edinburgh's memorial service alongside many of his family members on Tuesday.
The heartfelt service marked an emotional day for the royals as they celebrated the life of Prince Philip, who died last April at the age of 99.
Prince Charles was photographed at Sandringham on Sunday. Image: Geoff Robinson Photography
As well as Charles and Camilla, the Queen was also supported by Prince William and Kate, Princess Anne and Sir Tim Laurence, and the Earl and Countess of Wessex.
Princesses Beatrice and Eugenie and their respective husbands, Edoardo Mapelli Mozzi and Jack Brooksbank, and Lady Louise Windsor and James, Viscount Severn were also in attendance.
The Prince attended church at the Norfolk estate. Image: Geoff Robinson Photography
Image: Geoff Robinson Photography
Later in the week, Charles and Camilla opened the new headquarters of Meta, the parent company of Facebook and Instagram, but they did so in a high-tech way – using a touchscreen!
The royals were told by a representative: "We know that you unveil a lot of buildings, so we thought we'd do it with a Meta twist." The future King and Queen Consort were then given a tour of the capacious building, which will be home to 5,000 workstations.
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