The royal couple revealed they have chosen the Wilcocks Nursery School, in London, where Charlotte will be a pupil from 2018.
It came as Prince William and Kate shared a new photograph of their family. The image features on Their Royal Highnesses' Christmas card this year.
The photograph was taken earlier this year by Getty's royal photographer Chris Jackson at KensingtonPalace.
A spokesman for the Willcocks Nursery School said: "We are delighted that The Duke and Duchess of Cambridge have chosen the Willcocks Nursery School for Princess Charlotte.
"We look forward to welcoming Charlotte to our nursery in January."
Elder sibling and third-in-line to the throne Prince George currently attends the £17,604 a year Thomas's Battersea day school.
Kate is currently expecting her third child with Prince William, due in April 2018 - only a month before the Duke's brother Prince Harry is due to marry American actress Meghan Markle at Windsor Castle.
Ms Markle and fiance Prince Harry will be seen in public with other royals when they attend the traditional Christmas Day church service on the Queen’s private estate in Norfolk.
The couple got engaged on November 27 and a few days later a proud Harry introduced his bride-to-be to the nation during a series of official events in Nottingham.
Buckingham Palace has said the Queen and other members of the royal family will join the congregation for the morning service at St Mary Magdalene Church on December 25.
The couple are due to marry on May 19 2018.