K. International School Tokyo

Tokyo's strongest IB Diploma performer, a full PYP through DP school in Koto-ku that families pick for academic outcomes and accept the intensity that comes with them.

KIST runs the full IB continuum from age 3 to 18 on a modern campus in Shirakawa, Koto-ku. The class of 2025 averaged 42.0 on the IB Diploma, among the highest in Japan, and graduates head to Oxford, Cambridge and Ivy League destinations. Tuition runs notably lower than ASIJ, BST or Sacred Heart while the academic profile remains in the top tier. CIS accreditation is in place.

The trade-off is well documented. Parents and former students describe a study-focused environment with limited sports, drama and arts space compared to the larger Tokyo names. Families who want their child to thrive academically and are clear-eyed about the workload tend to be happy. Families looking for the broader extracurricular experience often look elsewhere. Communication with parents is strong, and the head, Kevin Yoshihara, is a long-tenured presence.

• One of Japan's strongest IB schools by results. Latest Diploma cohort averaged 42.3 points, with 90% of students scoring 40 or more; one Reddit teacher comment claims fourth in the world for IB scores.
• Discipline is unusually tight for an international school: blazers compulsory, hair dye and piercings banned, dress-code enforcement strict.
• Parents report clear academic expectations, regular measurement and proactive intervention. Communication with families is rated highly.
• Compensation for staff is mid-tier for Tokyo. One r/Internationalteachers commenter quoted a ~JPY 450,000-470,000 monthly base for a humanities teacher and called the working hours brutal: "They bleed you dry and pay you fuck all to take advantage of you wanting to live in Japan."
• Parents flag missing sports and drama facilities and activities relative to fees, which some say cuts against a whole-child experience.