The proud parents waved for a couple of moments before going back into the hospital.
"Their Royal Highnesses would like to thank all staff at the hospital for the care and treatment they have all received," Kensington Palace announced on Twitter. "They would also like to thank everyone for their warm wishes."
After her birth, Prince William went to fetch Prince George to come and meet his little sister. The little prince then returned to the palace after his visit.
Following the the princess' debut, Will and Kate packed up their baby girl in a car seat and returned to Kensington Palace. From entering the hospital to checking out, the whole process only took 12 hours. That must be some new royal record?
For more details about the royal baby, watch the video below: