Prince George, Princess Charlotte and Prince Louis showed their playful sides as they enjoyed their mother’s creation at the Chelsea Flower Show.
The Duchess of Cambridge will unveil the garden she designed for the event in London this week.
The royal children were captured trying it out as they spent an hour playing in the Back to Nature Garden on Sunday.
Charlotte is seen on a swing, while a barefoot George is paddling in a stream as an excited Louis runs with a branch.
Over the past months, George, Charlotte and Louis helped their mother collect leaves, moss and twigs which were then incorporated into the garden.
The Duke of Cambridge can also be seen playing with his family in the pictures released by Kensington Palace – and taken by photographer Matt Porteous.
Catherine has been closely involved in the project from the very beginning and has been at the site frequently ahead of the event, which opens on Tuesday.
The space features a tree house, waterfall, rustic den and a campfire as well as tree stumps, stepping stones and a hollow log for children to play on.
The duchess’s woodland wilderness plot forms part of her work on early childhood development.
Co-created with landscape architects Andrée Davies and Adam White, along with the Royal Horticultural Society, the garden is intended by the duchess to highlight the benefits the natural world brings to mental and physical well-being.
The duchess told the BBC: “I really feel that nature and being interactive outdoors has huge benefits on our physical and mental well-being, particularly for young children.
“I really hope that this woodland that we have created really inspires families, kids and communities to get outside, enjoy nature and the outdoors, and spend quality time together.”
Her conversation with Monty Don will air on Monday 20 May at 19.30 BST on BBC One.