Aoba-Japan International School vs Seisen International School
🇯🇵 Tokyo · Side-by-side comparison on verifiable public data.
Neither Aoba-Japan International School 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. Both run the same curriculum (IB), so the differences come down to pathway detail, campus culture, and specific language/boarding arrangements rather than the curriculum framework itself. 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
| Aoba-Japan International School | Seisen International School | |
|---|---|---|
| Curriculum | IB | IB |
| Ages | 2–18 | 2–18 |
| Languages of instruction | English | English |
| Annual fees | JPY 2,330,500–3,094,500 | JPY 2,650,000–2,850,000 |
| Enrollment | 600 | 695 |
| Boarding | Day only | Day only |
| Accreditations | CIS, NEASC | CIS, NEASC, JCIS |
Strengths
- ✓Long operating history (since 1976) and IB World School status since 2015
- ✓Dual external accreditation (CIS + NEASC) plus IB authorization
- ✓Distinctive entrepreneurship/innovation positioning, backed by BBT's business-education parentage
- ✓Strong language-inclusion model: native-English faculty plus integrated Intensive English Preparation through Grade 8
- ✓High diversity (~50 nationalities) while remaining accessible to Japanese-heritage families
- ✓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
- !'Full IB Continuum' marketing vs. evidence that MYP may be candidate-stage, not authorized — a continuity gap in the middle years
- !Multi-campus, age-split sites (2–6 vs 3–15 vs 15–18) can mean transitions between physical campuses
- !No published verified IB average — only a reported range (27–40); cohort-level outcomes not transparently public
- !Heavily Japanese-connected student body (~65% with at least one Japanese parent) may dilute the international-immersion some expat families expect
- !Accreditation/authorization detail relies partly on a Wikipedia article with maintenance flags
- !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
- • Families (esp. Japan-resident or mixed-heritage) wanting an English-medium IB pathway with strong EAL onboarding
- • Students drawn to entrepreneurship, innovation and project/STEAM-oriented learning
- • Families needing a 2-to-18 single-provider pathway in northwest/central Tokyo
- • 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
School-reported, unverified: IB Diploma results cited as a range of 27–40, with 100% of graduates progressing to further education. No published average score or independently verified destination list was found.
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.
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Frequently Asked Questions
Should I choose Aoba-Japan International School or Seisen International School?
Aoba-Japan International School is best for: Families (esp. Japan-resident or mixed-heritage) wanting an English-medium IB pathway with strong EAL onboarding. 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 Aoba-Japan International School and Seisen International School?
Aoba-Japan International School: JPY 2,330,500–3,094,500. 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 Aoba-Japan International School and Seisen International School offer?
Aoba-Japan International School: IB. Seisen International School: IB.
Do Aoba-Japan International School or Seisen International School offer boarding?
Aoba-Japan International School: 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 →