The Japan international goalkeeper has signed a contract which will keep her at the Joie Stadium until the summer of 2027.
A five-time Nadeshiko League Best Eleven inductee, the 2022/23 WE League Most Valuable Player arrives in England following an illustrious spell in her home country - winning 15 trophies.
But she believes now is the right time to join Gareth Taylor’s side and take on a new challenge.
“First of all, it is a great honour to join such a wonderful club and team. I feel very honoured to be here,” she declared.
“It’s also exciting to join a team with Ederson, whom I admire, and to wear the same shirt. I’m really looking forward to it.
“Because of my personality, I am very hungry. I’ve won various trophies in Asia, but to level up myself, I felt the need to take on a challenge.
“It’s a famous club that everyone knows, and even now, it feels unbelievable to me.
“Last season was really close, I thought that while watching the games from Japan. I want to support the team in winning titles, and contribute to the team.
“Please support us.”
After completing her City medical and media duties, Yamashita was also given a tour of the state-of-the-art City Football Academy.
The Club’s training ground has been the home of our women’s team since 2015, but plans were submitted in January 2024 for a purpose-built facility for Taylor’s team.
And the Japan international says the environment at the Blues will help her concentrate on improving as a player.
She added: “The training grounds have natural grass, and the environment is amazing, something that is impossible in Japan.
“I think I can play without any stress. City are a large-scale club, so I think it’s an environment where I can focus on training.”