Kairi is a friend of Sora and Riku, and one of the seven "Princesses of Heart". Her name can be seen as the meaning "sea". She is 14 years old as of Kingdom Hearts and Chain of Memories, and is 15 in Kingdom Hearts 2.

She is voiced by Hayden Panettiere in the first two games and by Alyson Stoner in Re: Chain of Memories. In Japanese, she is voiced by Risa Uchida.