International School of London vs Southbank International School
🇬🇧 London · Side-by-side comparison on verifiable public data.
Both carry a public inspection verdict: International School of London is Ofsted "Good" 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. 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. On cost, Southbank International School has the noticeably lower entry fee — a material difference for budget-conscious families. See the table below for the figures, and verify against each school's own published fees.
Key Facts
| International School of London | Southbank International School | |
|---|---|---|
| Curriculum | IB | IB |
| Ages | 3-18 | 2-18 |
| Languages of instruction | English | English |
| Annual fees | £24,630–£39,640/year (2026/2027, ages 3–17; figures incl. VAT where applicable) | £6,724-£16,033 per term (2025/26 Early Childhood half-day to DP; 2026/27 DP up to £16,033) |
| Enrollment | — | 800 |
| Boarding | Day only | Day only |
| Inspection rating | Ofsted: Good | Independent Schools Inspectorate (ISI): Met all standards (2024-2025, post-2023 framework) |
| Accreditations | Council of International Schools (CIS), International Baccalaureate Organization (IBO) | IB World School (PYP, MYP, DP), Independent Schools Association (ISA) member, ISI-inspected independent school |
Strengths
- ✓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
- ✓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
- !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
- !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 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
- • 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: 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.
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.
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Frequently Asked Questions
Should I choose International School of London or Southbank International School?
International School of London is best for: Internationally mobile families wanting a globally portable 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 International School of London and Southbank International School?
International School of London: £24,630–£39,640/year (2026/2027, ages 3–17; figures incl. VAT where applicable). 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 International School of London and Southbank International School offer?
International School of London: IB. Southbank International School: IB. International School of London inspection: Ofsted "Good". Southbank International School inspection: Independent Schools Inspectorate (ISI) "Met all standards (2024-2025, post-2023 framework)".
Do International School of London or Southbank International School offer boarding?
International School of London: day school only. 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 →