In the 1990s, as Kate Middleton, she attended Marlborough College, a top boarding school, where she played well at both field hockey and cross-country running, and was famously photographed with her hockey stick.
When Kate attended the Scottish University of St Andrews in 2001 she participated in a charity fashion show where Prince William sat in the front row, and at which she wore a stunning sheer black sheath over a bandeau top and bikini bottom, photos of which were carried by British and overseas tabloid newspapers.
It was also admitted after her wedding by dress designer Sarah Burton, of Alexander McQueen, that Kate had very strong ideas on the kind of dress she wanted to wear to Westminster Abbey and, in effect, created her own wedding dress. From these facts we can deduce that Kate has a strong interest in all aspects of fashion and fashion design.
In 2004 Kate and Prince William were photographed by the tabloids enjoying a Swiss ski holiday together at Klosters, from which it is clear that she enjoys, or at least participates in skiing.
But whatever hobbies and past times she may have enjoyed before joining the Royal family, she is certain to acquire many more new interests now that she has married. The Royal family is famously sporty and Prince William follows the family tradition. First there is everything to do with horses - racing, show jumping, eventing, carriage driving. Then there are field sports, such as shooting and fishing in which the Duchess of Cambridge is almost certain to indulge, if only to keep her husband and members of her new family company.