Marymount International School London vs TASIS The American School in England
🇬🇧 London · Side-by-side comparison on verifiable public data.
Reviewed by Priscilla Han
Which should you choose?
Both run IB, so the difference is inspection rating, boarding, and fees rather than the curriculum itself; both carry a public inspection verdict (Marymount International School London: Independent Schools Inspectorate (ISI) "Excellent"; TASIS The American School in England: Independent Schools Inspectorate (ISI) "Met all standards (2023 routine, post-2023 framework)") you can compare directly. The choice comes down to target curriculum, whether you need boarding, and budget — verify fees against each school's own figures.
Both carry a public inspection verdict: Marymount International School London is Independent Schools Inspectorate (ISI) "Excellent" and TASIS The American School in England is Independent Schools Inspectorate (ISI) "Met all standards (2023 routine, post-2023 framework)" — a rare pairing where an official quality rating can be compared head-to-head. On cost, TASIS The American School in England 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
| Marymount International School London | TASIS The American School in England | |
|---|---|---|
| Curriculum | IB | American / IB |
| Ages | 11-18 | 3-18 |
| Languages of instruction | English | English |
| Annual fees | Day GBP 39,540/yr; full boarding GBP 66,990/yr (2026-27, incl. VAT) | Day £15,600-£37,170/yr; boarding £69,650/yr (2026-27, inc. VAT) |
| Enrollment | 250 | 646 |
| Boarding | Yes | Yes |
| Inspection rating | Independent Schools Inspectorate (ISI): Excellent | Independent Schools Inspectorate (ISI): Met all standards (2023 routine, post-2023 framework) |
| Accreditations | Council of International Schools (CIS), Middle States Association of Colleges and Schools, International Baccalaureate Organisation (IBO) | NEASC, CIS, IB, ISA |
Strengths
- ✓ISI 'Excellent' Educational Quality outcome (2022) plus CIS, Middle States and IBO accreditation
- ✓Pioneer IB credentials — adopted the IB as its main curriculum in 1979, among the first in England
- ✓Strong, consistent IB Diploma outcomes (37-point average, 100% pass rate, Class of 2025)
- ✓Small ~250-student, multi-nationality community giving high individual attention
- ✓Established girls' boarding option within a values-led Catholic RSHM ethos
- ✓Dual American Diploma plus AP and IB Diploma pathways, giving families genuine curriculum choice in the Upper School
- ✓Triple accreditation by NEASC, CIS and the IB, plus ISA membership and ISI inspection
- ✓Highly international community of more than 70 nationalities
- ✓Boarding available from age 13, with a green Surrey campus close to London and Heathrow
- ✓Dedicated International Section providing English-as-an-additional-language support
Trade-offs
- !No IB Primary Years Programme — provision starts at age 11, so no early-years or primary pathway
- !Very small enrolment limits breadth of co-curricular and peer cohort scale
- !Premium fees (GBP 39,540 day / up to GBP 66,990 full boarding for 2026-27)
- !Single-curriculum (IB only) with no A-level or alternative-pathway fallback
- !Fees sit at the premium end, with full-year boarding at £69,650 and senior day fees above £37,000
- !No published verbatim 'Excellent' ISI grade, as recent inspections use the met / not-met framework
- !Less suited to families seeking a British GCSE / A-Level route, which the school does not offer
- !Quantitative IB and AP results are not prominently published, limiting outcome comparison
Best Fit For
- • Families seeking an all-girls, values-led Catholic education
- • Internationally mobile families wanting a recognised full IB Diploma pathway
- • Students aged 11+ who thrive in a small, close-knit cohort
- • Families needing girls' boarding (full, weekly or flexi) near London
- • American and international families wanting a US-style education near London
- • Students who may relocate within the global TASIS or US university system
- • Families seeking a choice between AP and the IB Diploma under one roof
- • Boarders aged 13-18 wanting a campus close to Heathrow
University Placement
School-reported · not independently verified
School-reported, unverified: graduates are described as progressing to top-tier universities worldwide, with around a third earning a bilingual IB diploma (Class of 2025).
School-reported, unverified: graduates pursue admission to universities in the United States, the United Kingdom and worldwide; specific destination data was not verified from a primary source.
More Comparisons
Frequently Asked Questions
Should I choose Marymount International School London or TASIS The American School in England?
Marymount International School London is best for: Families seeking an all-girls, values-led Catholic education. TASIS The American School in England is best for: American and international families wanting a US-style education near London. The right choice depends on target curriculum, budget, and family priorities — the two are not linearly comparable.
How do fees compare between Marymount International School London and TASIS The American School in England?
Marymount International School London: Day GBP 39,540/yr; full boarding GBP 66,990/yr (2026-27, incl. VAT). TASIS The American School in England: Day £15,600-£37,170/yr; boarding £69,650/yr (2026-27, inc. VAT). Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do Marymount International School London and TASIS The American School in England offer?
Marymount International School London: IB. TASIS The American School in England: American, IB. Marymount International School London inspection: Independent Schools Inspectorate (ISI) "Excellent". TASIS The American School in England inspection: Independent Schools Inspectorate (ISI) "Met all standards (2023 routine, post-2023 framework)".
Do Marymount International School London or TASIS The American School in England offer boarding?
Marymount International School London: offers boarding. TASIS The American School in England: offers boarding.
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 →