The royal siblings were spotted on another yacht with their grandparents Michael, 70, and Carole Middleton, 64.
Six-year-old George wore a captain’s hat and a life jacket over his H&M navy and white striped polo top (available only in the white colourway for £7.99) as he watched the eight boat race.
He flashed a gap toothed smile as Kate, 37, and William, 37, went head-to-head alongside celebrities to raise awareness and funds for eight of their patronages.
Princess Charlotte, four, could be seen sitting inside the boat, wearing a blue striped dress with a white Peter Pan collar.
According to reports, Kate and William’s youngest child Prince Louis, one, was also in Cowes on the day.
Earlier today, the Duchess of Cambridge was spotted wearing an £81 striped Sandro top with her LK Bennett sailor pants and Superga trainers.
She later changed into a sailing jacket, polo top, shorts and New Balance sneakers.
Prince George celebrated his birthday last month before heading off on holiday with his parents and younger siblings. Photos of him wearing an England football shirt were released to mark the occasion.
The Cambridges spent two weeks in a £27,000 luxury villa on the private Caribbean island Mustique.
The children were last seen in public at the King Power Royal Charity Polo Day in July, where they watched dad William play alongside uncle Harry.
The Cambridge children met their baby cousin Archie for the first time at the event.
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