ACS International Schools vs International School of London
🇬🇧 London · Side-by-side comparison on verifiable public data.
Both carry a public inspection verdict: ACS International Schools is Independent Schools Inspectorate (ISI) "Met all standards (2025 EQI, post-2023 framework)" and International School of London is Ofsted "Good" — a rare pairing where an official quality rating can be compared head-to-head. One practical difference: ACS International Schools 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
| ACS International Schools | International School of London | |
|---|---|---|
| Curriculum | American / IB | IB |
| Ages | 2-18 (Cobham); 3-18 (Egham, Hillingdon) | 3-18 |
| Languages of instruction | English | English |
| Annual fees | ACS Cobham 2026-2027 day tuition GBP 9,950-39,960/yr; 7-day boarding (Grades 8-12) up to GBP 69,060/yr inclusive | £24,630–£39,640/year (2026/2027, ages 3–17; figures incl. VAT where applicable) |
| Enrollment | 2,200 | — |
| Boarding | Yes | Day only |
| Inspection rating | Independent Schools Inspectorate (ISI): Met all standards (2025 EQI, post-2023 framework) | Ofsted: Good |
| Accreditations | New England Association of Schools and Colleges (NEASC), College Board, International Baccalaureate Organization, Educational Collaborative for International Schools (ECIS), Independent Schools Association (ISA) | Council of International Schools (CIS), International Baccalaureate Organization (IBO) |
Strengths
- ✓Dual American (High School Diploma plus AP) and IB pathways under one operator, rare in the London market
- ✓ACS Egham offers all four IB programmes (PYP, MYP, DP, CP) - a full through-IB continuum
- ✓Highly international community of 70+ nationalities with structured EAL and home-language support
- ✓Long-established (since 1967) with NEASC accreditation and College Board / IB partnerships
- ✓Boarding available at Cobham (Grades 8-12), including flexible temporary boarding options
- ✓Exceptional mother-tongue programme — 24 home languages taught as part of the curriculum, a genuine sector outlier
- ✓Strong bilingual outcomes — about half of leavers earn the bilingual IB Diploma, well above the IB world average
- ✓Full IB continuum (PYP, MYP, DP) under one provider, giving age-3-to-18 curricular coherence
- ✓Long pedigree and accreditation — founded 1972, CIS-accredited, authorised IB World School (code 000057)
- ✓Genuinely international and non-selective — 54 student nationalities across the IB programmes, open admissions
Trade-offs
- !Premium fees, with senior-year day tuition near GBP 40,000 and full boarding around GBP 69,000 a year at Cobham
- !IB continuum breadth (all four programmes) is concentrated at Egham, not uniform across all three campuses
- !IGCSE is not offered, so families wanting a British GCSE route are not served
- !Current ISI framework yields a 'met all standards' outcome rather than a published top graded band
- !Ofsted rating is 'Good', not 'Outstanding', so it is not in the top inspection band
- !High fees (up to £39,640/year) place it among the more expensive London options
- !Split-site model (Chiswick primary/middle, Ealing Diploma College) rather than a single campus
- !No British (A-level/GCSE) or American track for families wanting a non-IB pathway
Best Fit For
- • Internationally mobile families wanting a US diploma plus AP and/or IB pathway
- • Students targeting US university applications who value AP and a transcript-based diploma
- • Families needing boarding within commuting distance of London (Cobham)
- • Children needing EAL support within a multinational peer group
- • Internationally mobile families wanting a globally portable IB pathway
- • Multilingual households wanting their child's mother tongue actively maintained
- • Students who will sit the bilingual IB Diploma
- • Families seeking a non-selective school with a strong EAL on-ramp into English
University Placement
School-reported · not independently verified
School-reported, unverified: ACS promotes US and international university destinations across its alumni, but no independently verified placement figures were found.
School-reported, unverified: published higher-education destinations (2012–2025 dataset) include King's College London, UCL, Imperial College London, Warwick, Edinburgh, Manchester and Bristol in the UK, plus international destinations such as Bocconi, Sciences Po, McGill, University of Toronto, University of Chicago and Keio University.
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Frequently Asked Questions
Should I choose ACS International Schools or International School of London?
ACS International Schools is best for: Internationally mobile families wanting a US diploma plus AP and/or IB pathway. International School of London is best for: Internationally mobile families wanting a globally portable IB pathway. The right choice depends on target curriculum, budget, and family priorities — the two are not linearly comparable.
How do fees compare between ACS International Schools and International School of London?
ACS International Schools: ACS Cobham 2026-2027 day tuition GBP 9,950-39,960/yr; 7-day boarding (Grades 8-12) up to GBP 69,060/yr inclusive. International School of London: £24,630–£39,640/year (2026/2027, ages 3–17; figures incl. VAT where applicable). Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do ACS International Schools and International School of London offer?
ACS International Schools: American, IB. International School of London: IB. ACS International Schools inspection: Independent Schools Inspectorate (ISI) "Met all standards (2025 EQI, post-2023 framework)". International School of London inspection: Ofsted "Good".
Do ACS International Schools or International School of London offer boarding?
ACS International Schools: offers boarding. International School of London: day school only.
Questions parents ask
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 →