William's four charitable causes are Child Bereavement UK, Centerpoint, London’s Air Ambulance Charity and Tusk.
The Duke of Cambridge will be competing alongside English footballer Fara Williams, historian Dan Snow, and TV personality Bear Grylls in his boat.
Meanwhile Kate will be on behalf of the Royal Foundation and will be joined by comedian John Bishop for Action on Addiction, children’s TV presenter Katie Thistleton for Place2Be, and British Olympic rower Helen Glover for the Anna Freud Centre.
The royal couple have always been fiercely competitive, having already raced each other in a sailing competition back in 2014.
While in New Zealand, the Cambridge's decided to try their hand at racing America’s Cup sailing boats in Auckland.
Unluckily for William, his wife beat him in New Zealand...twice!