Harrow International School Bangkok vs International School Bangkok
🇹🇭 Bangkok · Side-by-side comparison on verifiable public data.
Harrow International School Bangkok holds a public inspection verdict (BSO "Outstanding"), while International School Bangkok operates in a market with no public inspectorate — so the former has a verifiable official quality anchor and the latter is judged on accreditation depth. Curriculum is the core differentiator: Harrow International School Bangkok offers British while International School Bangkok offers American, IB — the choice should follow the family's target qualification system. One practical difference: Harrow International School Bangkok offers boarding while the other is day-only — decisive for families who need a residential option. Verify current fees against each school's own figures (see the table below).
Key Facts
| Harrow International School Bangkok | International School Bangkok | |
|---|---|---|
| Curriculum | British | American / IB |
| Ages | 18 months–18 years | 3–18 |
| Languages of instruction | English | English |
| Annual fees | THB 136,800–1,037,100 | THB 659,000–1,197,000 |
| Enrollment | 1,713 | 1,700 |
| Boarding | Yes | Day only |
| Inspection rating | BSO: Outstanding | — |
| Accreditations | CIS, FOBISIA, HMC, ISAT, BSO | WASC, CIS, EARCOS, ISAT |
Strengths
- ✓Published BSO 'Outstanding' (Grade 1) rating, March 2023 — Ofsted-quality-assured, verbatim band, the rare Outstanding-equivalent that earns top inspection tier
- ✓The original Harrow international school (1998) with the strongest brand heritage of any Harrow Asia campus
- ✓Genuine, well-developed boarding provision (boarding village, multiple houses) — uncommon in Bangkok
- ✓Strong inspection-verified academics: outstanding English/maths/science attainment, A*–A-heavy A-level and IGCSE outcomes (2023)
- ✓Documented EAL support: the BSO report records 1,590 EAL pupils receiving provision and making strong progress
- ✓70+ year track record as Thailand's first international school, with institutional stability and a large ~1,700-student community
- ✓Dual university pathways — both IB Diploma and AP available within one school, plus an ISB Diploma option
- ✓Strong published IB results: Class of 2025 average 34, top score 44, 16% scoring 40+
- ✓Deep accreditation: both WASC and CIS, plus IB authorisation
- ✓Diverse community spanning 60+ nationalities
Trade-offs
- !Premium fees: tuition runs up to THB ~1.04M/year, with boarding adding THB 445,600–557,200 — among the most expensive options in Bangkok
- !For-profit ownership: operated commercially by AISL Group under franchise license, not an independent non-profit foundation
- !Not IB: families wanting the IB Diploma must look elsewhere — the offering is strictly British IGCSE/A-Level
- !Latest published BSO inspection is 2023; no newer independently published rating confirmed
- !Academic results are inspection/school-reported, not annually re-verified by an external body
- !Premium fees: high-school tuition THB 1,197,000/year plus a THB 260,000 one-time registration fee place ISB at the top of the Bangkok market
- !EAL/ESL support is not described on public pages — families needing English-language support cannot verify provision
- !Located in Nichada Thani (Pakkret, Nonthaburi), well north of central Bangkok — a commute consideration
- !Exact campus size/acreage is not published
- !No boarding option, so it serves only families resident in the area
Best Fit For
- • Families seeking a genuine British boarding experience in Asia (day option also available)
- • Families prioritising a verified 'Outstanding' inspection record and A-Level/Oxbridge-style university pathways
- • Internationally mobile or regional families wanting weekly or full boarding
- • Those who value the Harrow brand heritage and traditional House System
- • Expatriate and internationally mobile families wanting a stable American-curriculum school with US university orientation
- • Students who want to choose between IB Diploma and AP routes within a single school
- • Families already living in or near the Nichada Thani / northern Bangkok area
- • High-achieving students targeting selective North American and global universities
University Placement
School-reported · not independently verified
School-reported, unverified for current year. The 2023 BSO report stated A-Level results were 'outstanding' with almost all pupils achieving A*–A grades and 65% of IGCSE entries at A*–A, with pupils 'securing places in prestigious universities worldwide.' No independently verified, current-year university-destination list is public.
School-reported, unverified: ISB reports Class of 2025 matriculation including Stanford, Cornell, UC Berkeley, UCLA, NUS, UCL and University of Toronto. ISB offers AP rather than A-Levels; 277 AP exams were completed in 2025. Figures are school-published and not independently verified.
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Frequently Asked Questions
Should I choose Harrow International School Bangkok or International School Bangkok?
Harrow International School Bangkok is best for: Families seeking a genuine British boarding experience in Asia (day option also available). International School Bangkok is best for: Expatriate and internationally mobile families wanting a stable American-curriculum school with US university orientation. The right choice depends on target curriculum, budget, and family priorities — the two are not linearly comparable.
How do fees compare between Harrow International School Bangkok and International School Bangkok?
Harrow International School Bangkok: THB 136,800–1,037,100. International School Bangkok: THB 659,000–1,197,000. Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do Harrow International School Bangkok and International School Bangkok offer?
Harrow International School Bangkok: British. International School Bangkok: American, IB. Harrow International School Bangkok inspection: BSO "Outstanding".
Do Harrow International School Bangkok or International School Bangkok offer boarding?
Harrow International School Bangkok: offers boarding. International School Bangkok: 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 →