Balmoral is an important place for the Royal Family, and is one of the Queen's favourite places in the world. It's where she's able to engage in many of her passions and spend time outdoors while on (relative) vacation. It's also been very important for other royals, with Prince William and Prince Harry having much of spent their childhoods there with Prince Charles, Princess Diana and other family members through the years.
With the school year set to begin over the next few days in the U.K., it was important for Prince George, Princess Charlotte and Prince Louis to get some time in with their Gan Gan before hitting the books. William and Duchess Kate reportedly took their three kids up to Scotland to see their great-grandmother in August, according to HELLO! UK.
Her Majesty has been at Balmoral since late July, and was given an official welcome early the following month. It is her first summer there without late husband Prince Philip, who passed away at age 99 in April. She's had several visitors since then, including Sarah Ferguson, Prince Andrew and Princess Eugenie and Jack Brooksbank and Charlesand Duchess Camilla.
This was likely a very welcome and happy trip for the Cambridge kids, especially with everything that's gone on with the coronavirus pandemic in the last 18 months. The Queen and the Duke and Duchess of Cambridge are now all vaccinated, so that makes seeing family a bit easier, though the Delta variant is still obviously a concern.
Later this month, Charlotte and George will resume their studies at Thomas's Battersea school in London, where they're set to start Year 2 and Year 4, respectively. Little Louis, who turned three years old in April, will also head back to Willcocks Nursery School after having started there during the spring.
This isn't the first time the Cambridges have been up to Scotland this year. Back in May, William and Kate went on a mini tour of the country that saw them return to the University of St. Andrews, where they first met. No doubt they're looking forward to returning to work and resuming their royal duties after a summer that also saw them travel to the Isles of Scilly near Cornwall for a family getaway. They also spent time there in 2020, having a staycation amidst the pandemic.
Normally in the summer, the Cambridges travel to Mustique in the Caribbean to spend time there together, but that has been difficult due to COVID-19 restrictions for the last two summers.