Seisen International SchoolVerified

In Brief

For families with daughters who thrive in an academically focused, values-led environment, Seisen is one of the strongest IB girls schools in Asia. A 97.7% Diploma pass rate and average score of 35 in 2025 are the numbers that matter. If you want a co-ed school or a school with broad co-curricular scale, look elsewhere.

Seisen is one of the 'big four' Tokyo international schools and the go-to option for families with daughters who want a serious IB education in a Catholic girls environment. With 650 students from 55+ nationalities in Yoga, Setagaya, it is deliberately kept small - a maximum of 50 students per year group. Japan's first all-girls school to offer the IB Diploma (1986) and the first to achieve full IB Continuum status (2020), it has built a consistent academic record: a 2025 Diploma average of 35 and a 97.7% pass rate are both well above global norms.

The academic culture runs deep. The Firebird science team competes internationally in STEM competitions. The Duke of Edinburgh programme, a competitive debate team, and a National Honor Society chapter sit alongside a house system that creates vertical friendships across year groups. Graduates spread broadly: roughly 60% go to North American universities (including Harvard, Princeton, Columbia, and Stanford in recent years), 20% to the UK and Europe, and 20% to Japanese universities including Waseda, Keio, and Sophia (the Catholic connection helps with Sophia). Despite being all-girls from Grade 1, kindergarten is co-ed.

Facilities are functional rather than impressive by Tokyo international standards - families coming from larger co-ed schools mention the campus feels compact and the sports infrastructure is limited compared to ASIJ. The Yoga (Setagaya) location puts it in the residential south-west; from Minato-ku you are looking at 30-40 minutes. The Catholic ethos is present but non-coercive - students do not need to be Christian, and many are not. Religious classes are positioned as ethics and character formation, and families from non-Christian backgrounds generally find this manageable.