ACS International Schools vs Southbank International School
🇬🇧 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 Southbank International School is Independent Schools Inspectorate (ISI) "Met all standards (2024-2025, post-2023 framework)" — 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 | Southbank International School | |
|---|---|---|
| Curriculum | American / IB | IB |
| Ages | 2-18 (Cobham); 3-18 (Egham, Hillingdon) | 2-18 |
| 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 | £6,724-£16,033 per term (2025/26 Early Childhood half-day to DP; 2026/27 DP up to £16,033) |
| Enrollment | 2,200 | 800 |
| Boarding | Yes | Day only |
| Inspection rating | Independent Schools Inspectorate (ISI): Met all standards (2025 EQI, post-2023 framework) | Independent Schools Inspectorate (ISI): Met all standards (2024-2025, post-2023 framework) |
| Accreditations | New England Association of Schools and Colleges (NEASC), College Board, International Baccalaureate Organization, Educational Collaborative for International Schools (ECIS), Independent Schools Association (ISA) | IB World School (PYP, MYP, DP), Independent Schools Association (ISA) member, ISI-inspected independent school |
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
- ✓Full IB continuum (PYP, MYP, DP) authorised end-to-end, ages 2-18, within one school
- ✓Strong published DP outcomes: Class of 2025 average of 35.4 against a 30.58 global average, with three perfect 45 scores
- ✓Highly international community of around 70 nationalities reinforcing genuine international-mindedness
- ✓Embedded EAL support enabling students with little or no English to access PYP and MYP
- ✓Central-London campuses across Hampstead, Kensington and Westminster offering catchment flexibility
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
- !Premium fees, with DP at up to £16,033 per term inc. VAT for 2026/27 plus deposit and capital charges
- !Recent ISI inspections use a met / not-met framework, so no top graded band evidences excellence
- !Programmes split across separate campuses rather than one continuous all-through site
- !Day-only school with no boarding provision
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 single IB pathway from age 2 to 18
- • Students who thrive in a multilingual, multinational peer group
- • Families targeting strong IB Diploma results for university entry
- • Children needing structured EAL support to enter an English-medium programme
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: Southbank describes itself as 'London's leading International Baccalaureate (IB) School' and reports three Class of 2025 students scoring a perfect 45, placing them in the top 1% globally.
More Comparisons
Frequently Asked Questions
Should I choose ACS International Schools or Southbank International School?
ACS International Schools is best for: Internationally mobile families wanting a US diploma plus AP and/or IB pathway. Southbank International School is best for: Internationally mobile families wanting a single IB pathway from age 2 to 18. 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 Southbank International School?
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. Southbank International School: £6,724-£16,033 per term (2025/26 Early Childhood half-day to DP; 2026/27 DP up to £16,033). Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do ACS International Schools and Southbank International School offer?
ACS International Schools: American, IB. Southbank International School: IB. ACS International Schools inspection: Independent Schools Inspectorate (ISI) "Met all standards (2025 EQI, post-2023 framework)". Southbank International School inspection: Independent Schools Inspectorate (ISI) "Met all standards (2024-2025, post-2023 framework)".
Do ACS International Schools or Southbank International School offer boarding?
ACS International Schools: offers boarding. Southbank International School: 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 →