The American School in Japan vs Seisen International School
🇯🇵 Tokyo · Side-by-side comparison on verifiable public data.
Neither The American School in Japan nor Seisen International School sits in a market with a public inspectorate, so both are assessed on verifiable accreditation, curriculum authorisation, and published data rather than an official quality rating. Curriculum is the core differentiator: The American School in Japan offers American while Seisen International School offers IB — the choice should follow the family's target qualification system. Both are day schools with fees in the same market band — see the table below for the figures, and verify against each school's own published fees.
Key Facts
| The American School in Japan | Seisen International School | |
|---|---|---|
| Curriculum | American | IB |
| Ages | 3–18 | 2–18 |
| Languages of instruction | English | English |
| Annual fees | JPY 2,987,000–3,533,000 | JPY 2,650,000–2,850,000 |
| Enrollment | 1,734 | 695 |
| Boarding | Day only | Day only |
| Accreditations | WASC | CIS, NEASC, JCIS |
Strengths
- ✓Long-established institution (founded 1902), among the oldest international schools in Asia
- ✓WASC-accredited with a clearly American, AP-based college-preparatory curriculum
- ✓Substantial scale: ~1,734 students and ~184 teachers across two purpose-run Tokyo campuses
- ✓Genuinely international community spanning 59 nationalities
- ✓Full continuous pathway from Nursery (age 3) through Grade 12
- ✓Full IB continuum (PYP + MYP + DP) under one roof — strong vertical academic coherence
- ✓Strong dual international accreditation: CIS + NEASC, plus JCIS membership
- ✓Long-established (since 1962) with a clear, distinctive Catholic, girls'-school identity
- ✓Documented EAL support plus dedicated learning-support specialists
- ✓Small class sizes (average ~20) and a low reported student-faculty ratio
Trade-offs
- !Does NOT publish AP results or university-placement data — outcomes cannot be independently verified
- !Explicitly offers no scholarships or financial aid for new applicants, with high all-in costs
- !English-fluency requirement for at least one parent narrows the applicant pool
- !Day school only — no boarding
- !Public detail on EAL/English-language support could not be confirmed
- !IB Diploma results / average scores are not published — academic outcomes cannot be independently verified
- !Tuition is not published on the official site; fee data is third-party (school-reported) only
- !Single-sex from Grade 1 onward excludes boys beyond kindergarten
- !Catholic sponsorship may not suit families seeking a fully secular environment
- !No boarding — day-school only
Best Fit For
- • Expatriate and internationally-mobile families in Tokyo seeking a U.S. college-prep track
- • Families targeting American/AP university admission pathways
- • Households wanting a single continuous K–12 (age 3–18) institution
- • Families who can absorb premium fees without needing financial aid
- • Families seeking a single-sex environment for girls within a rigorous IB pathway
- • Families who value a faith-rooted (Catholic) ethos with cultural/religious inclusivity
- • Younger families wanting a co-ed start in kindergarten that transitions to girls-only
- • Students needing EAL support entering an English-medium IB programme
University Placement
School-reported · not independently verified
Not public. No university-placement, college-matriculation, or AP results data is published on ASIJ's public website (consistent with the norm among Tokyo international schools).
School-reported, unverified: Seisen reports that 98% of graduates proceed to a higher educational institution. No specific university-destination lists or IB score averages are published.
More Comparisons
Frequently Asked Questions
Should I choose The American School in Japan or Seisen International School?
The American School in Japan is best for: Expatriate and internationally-mobile families in Tokyo seeking a U.S. college-prep track. Seisen International School is best for: Families seeking a single-sex environment for girls within a rigorous IB pathway. The right choice depends on target curriculum, budget, and family priorities — the two are not linearly comparable.
How do fees compare between The American School in Japan and Seisen International School?
The American School in Japan: JPY 2,987,000–3,533,000. Seisen International School: JPY 2,650,000–2,850,000. Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do The American School in Japan and Seisen International School offer?
The American School in Japan: American. Seisen International School: IB.
Do The American School in Japan or Seisen International School offer boarding?
The American School in Japan: day school only. Seisen International School: day school only.
This comparison is BrightKey's independent assessment using verifiable public data only. University-placement figures are school-reported and not independently verified. BrightKey takes no payments from schools. Our method →