Prince George, who recently celebrated his 6th birthday, was all smiles for the adventure on the water.
Princess Charlotte took to the sea alongside her big brother.
While their parents took part in the race, George and Charlotte were looked after by their grandparents, Mike and Carole Middleton.
Grandpa Mike and George share a sweet moment on deck.
Kate arrived wearing a striped multi-color shirt with nautical-inspired slacks casually paired with white sneakers, while William stuck to his go-to look of a suit jacket over a button-up shirt sans tie.
The little royal was seen sporting a brand new look — a captain’s hat…
…along with a smile minus his two front teeth!
Charlotte, 4, was dressed appropriately for the nautical occasion, rocking blue and white stripes. (Her sleeveless dress is by Ralph Lauren Kids.)
While Kate and William were busy competing, they remained under the watchful eye of their grandparents.
Prince George took in the sights.
George and Charlotte are in total kid mode as they play with other young children at the event.
Kate and William changed into matching outfits for the race — a white polo shirt with blue shorts. The royal mom also tied her hair into a ponytail topped with a baseball cap, preventing her hair from providing a distraction during the competition.
The King’s Cup Regatta was originally scheduled for Friday, but due to forecasted bad weather in Cowes on the Isle of Wight, the race was moved up a day.
Kate and William each acted as skippers of competing vessels — state-of-the-art Fast-40 boats — for the chance to win the King’s Cup, a historic trophy first presented by King George V at Cowes’ Royal Yacht Squadron in 1920.
Eight boats took part in the race, each representing a charity being supported by the royals. This year, Kate’s four charities that were represented are Action on Addiction, Place2Be, the Anna Freud National Centre for Children and Families, and The Royal Foundation. Child Bereavement UK, Centrepoint, the London Air Ambulance Charity 30th Anniversary Campaign, and Tusk, four causes for which William is a patron, also competed. Tusk Trust, with Bear Grylls at the helm, won the first race, with Prince William coming in third and Kate placing seventh.
Members of the public were invited to watch the race from grandstands on the shore and enjoy family-friendly activities along the seafront.
The sporty couple are longtime advocates for being active, highlighting how sports, nature and being outdoors can improve physical and mental well-being.
And they’re not opposed to some friendly competition. While visiting Northern Ireland in March, Kate and William faced off against each other in a canoe race, where William’s boat clinched the victory. Despite falling short, the royal mom flashed a big smile while wearing her helmet and holding her paddle.