The filming locations for the Yoto High School that Aqua, Ruby, and Kana attend are:
The front of the school gate is Shukutoku Junior and Senior High School (Itabashi Ward, Tokyo)
The school grounds are Shukutoku Yono Junior and Senior High School (Saitama City, Saitama Prefecture)
They are affiliated schools.
When the extravagant uniforms from the original manga and anime are adapted into live-action, they tend to look like cosplay and stand out in a negative way.

Pilgrimage to the filming locations of the drama series: Yoto High School | エコー's post