In the first picture Charlotte, who turns four on Thursday, can be seen taking advantage of some of the unseasonably warm spring weather in a blue floral dress with a Peter Pan collar, the same one she wore to go and see her little brother, Prince Louis, in hospital for the first time last year.
Kate loves dressing her daughter in blue - it has featured in many of her official portraits - and Charlotte is wearing her hair pushed back off her head in a blue bow with navy Hampton canvas plum shoes,from her favourite children's High Street store, Trotters.
The shot was captured by Kate when she and her family returned to Kensington Palace last month after their Easter break and shows a bank of wildflowers in the background.
The other two pictures were taken by the Duchess as part of a set at Anmer Hall, on the same day that she and her elder brother, Prince George, five were seen attending the Burnham Horse Trials with their cousin, Mia Tindall, five.