Takarazuka, Hyōgo
Itahashi was born in Takarazuka, Hyōgo Prefecture. She commenced swimming at the JSS swimming school in Takarazuka when in her first grade of elementary school. When in the third grade she switched to diving after first participating in a one-month course. Her father is a former judo player. Her coach at JSS is , who is also head coach of the national diving team.