They shared spectacular images of the garden, co-designed by Kate, ahead of the Chelsea Flower Show which begins on Tuesday.
The 'Back to Nature' Garden includes a swing seat, hanging below the garden’s centrepiece, a high platform tree house as well as "incredible edibles, plants for craft activities, forest scents and a diverse range of plants, shrubs and trees of different heights and textures," Kensington Palace said.
The Duchess of Cambridge said of the garden: "In recent years, I have focused much of my work on the early years and how instrumental they are for outcomes later in life.
"I believe that spending time outdoors when we are young can play a role in laying the foundations for children to become happy, healthy adults."
The garden is aimed at inspiring children, families and communities to enjoy the great outdoors, the Palace said.
The garden was created in partnership with landscape architects Davies White and the Royal Horticultural Society and was inspired by the Duchess's childhood.
She used wild plants and natural materials to create a "woodland wilderness" that both children and adults can enjoy.
Sharing the first glimpse of the garden, Kate was pictured on a swing in a photo said to have been taken by a palace aide.
The garden features a bridge over a burbling brook and the quirky wooden treehouse as a centrepiece.
The garden also features bunches of forget-me-nots, Princess Diana's favourite flowers.
Next week marks one year since the Duchess of Cambridge and The Royal Foundation established an expert steering group on early years, to advise her on what more needed to be done to better support children in Britain.
The Duchess has committed to making early childhood development the focus of her work.
She wrote: “Through our work, you have reaffirmed my belief of just how timely it is to focus on what happens in the early years of life, and how pivotal a stage of life this is for a child’s future.”
The Duke and Duchess of Cambridge and Sussex have made championing mental health for young people a key focus of their work.