One of the reasons may be that Duchess Kate has a very exciting event next week which will see her compete with SailGP's GB team in Plymouth in a 'Commonwealth Race' against their New Zealand rivals, ahead of the final day of the Great Britain Sail Grand Prix.
WATCH: The Duke and Duchess of Cambridge's favourite holiday destinations
Kate, who is known for being a keen sportswoman, will become a member of the British crew, working with the rest of the team to race the boat at speeds of up to 50 knots (more than 55 mph) in a friendly race.
Whilst in Plymouth, Kate will also visit the 1851 Trust, whom she is patron of, to meet with youngsters taking part in the Trust’s activities to promote sustainability.
William and Kate hinted their UK staycation with a sweet birthday photo of George © The Duchess of Cambrige
The choice to enjoy the summer months in the UK may also be down to the major preparations the Duke and Duchess are making ahead of their expected move to Windsor.
Kate loves to get involved with sports
The big move from London, would mean the Cambridges would be closer to the Queen who now permanently lives at Windsor Castle.
Kate parents, Carole and Michael Middleton, and also her brother James, live in Berkshire which is a mere 40-minute drive from Windsor.
While the family will live in Windsor, William and Kate will continue to use Kensington Palace as their London base for work.
The Cambridges currently reside at their Kensington Palace apartment
Whilst the exact location of the family-of-five's holiday is yet to be revealed, royal fans did get a hint of their stunning getaway as William and Kate released a special beachside portrait of their son who turned nine on Friday.
The adorable new photo, which was taken by mum Kate earlier in the month, saw the youngster posing in a blue shirt.
Royal watchers all said the same thing about the stunning portrait, likening the young Prince to his father Prince William.
On the photo shared to Instagram, one follower penned: ""Wow he looks just like his Dad." A second wrote: "He looks just like William to me! Beautiful boy. Happy Birthday PG."
A third wrote: "What a fantastic photo! George looks so much like his dad." A fourth added: "Wow, a little William, spitting image."
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