The 42-year-old royal will accompany her husband Prince William and their three children, Prince George, 11, Princess Charlotte, nine, and six-year-old Prince Louis, as well as other members of the institution, to Scotland for their annual break, in what will be her longest journey since she was diagnosed with cancer earlier this year, sources told the Mail on Sunday newspaper.
After revealing in March she was undergoing preventative chemotherapy following abdominal surgery earlier in the year, Catherine has mostly divided her time between the family's Windsor home Adelaide Cottage and their holiday residence in Norfolk, Anmer Hall, with the two properties being around 125 miles apart.
The princess also made the short journey to London for Trooping the Colour in June and Wimbledon for the men's tennis final in July.
In June, Catherine revealed she is "making good progress" but still had "a few more months" of treatment to complete.
She said in a statement: "I have been blown away by all the kind messages of support and encouragement over the last couple of months. It really has made the world of difference to William and me and has helped us both through some of the harder times.
"I am making good progress, but as anyone going through chemotherapy will know, there are good days and bad days. On those bad days, you feel weak, tired and you have to give in to your body resting. But on the good days, when you feel stronger, you want to make the most of feeling well.
"My treatment is ongoing and will be for a few more months. On the days I feel well enough, it is a joy to engage with school life, spend personal time on the things that give me energy and positivity, as well as starting to do a little work from home."
Catherine also noted she would be making her first official public appearance at Trooping the Colour and even though she is "not out of the woods yet" with regards to her health, she is focusing on taking things one day at a time.
She said: "I'm looking forward to attending The King's Birthday Parade this weekend with my family and hope to join a few public engagements over the summer, but equally knowing I am not out of the woods yet.
"I am learning how to be patient, especially with uncertainty. Taking each day as it comes, listening to my body, and allowing myself to take this much-needed time to heal.
"Thank you so much for your continued understanding, and to all of you who have so bravely shared your stories with me."