The campus is located in central Tokyo and comprises six buildings: the Matsukata House, the Ushiba Memorial gymnasium/auditorium, the kindergarten building in the nearby Moto Azabu Hills complex, the primary building housing grades 1-2, the upper elementary/middle school building housing grades 3-9, and the new Yashiro Media Center. Matsukata House was the original family residence of Nishimachi's founder, Tane Matsukata, and now serves as the school's main administrative building. The Yashiro Media Center, housed in its own three-story building, contains about 18,000 volumes, 70% in English and 30% in Japanese. Nishimachi's outdoor education center, Camp Rioichiro Arai – “Kazuno,” is in Gunma Prefecture, 150 kilometers northwest of Tokyo.

Educational Programs: Nishimachi offers a unique, educational program where all students study in English and Japanese. Students study Japanese as a first or second language. Although the original curriculum was based on the American educational model, components from various international educational sources have been incorporated into the instructional program. This provides a very wide range of academic experiences. All subjects, with the exception of the Japanese language and Japanese social studies, are taught in English.

Nishimachi International School is ...
- Conveniently located in a residential pocket of central Tokyo favored by the diplomatic and expatriate communities.
- Small and intimate, which enables us to promote the optimal well-being and growth of each individual.
- Co-educational and non-sectarian - Kindergarten through Grade 9.
- A Pioneer in dual-language English and Japanese education in Japan.
- Multicultural with a student body of some 400 children representing twenty-five countries.
- Accredited by WASC (Western Association of Schools Committee), CIS (Council of International Schools), and recognized by the Tokyo Metropolitan Government.