St. Mary’s International School Tokyo Guide 2026: IB Diploma, 2026-27 Fees, Admissions and Results

St. Mary’s International School is an all-boys Catholic international school in Setagaya, Tokyo, teaching boys from its Readiness Program (kindergarten) through Grade 12. It was founded in 1954 and today has 976 students from 43 nationalities, according to its 2026-27 School Profile. If you are looking for an English-medium school for a son in Tokyo, and especially one that leads to the IB Diploma, it is likely to be on your list.

This guide pulls together what the school publishes about its curriculum, IB Diploma results, fees for the 2026-2027 school year and admissions, so you can see quickly whether it fits your family. It is based on the school’s official website, its 2026-27 School Profile and Program of Studies, and the Japanese Ministry of Education (MEXT) IB consortium list, all checked on 26 September 2026. Fees and dates change each year, so please confirm details with the school before you apply.

St. Mary’s at a glance

Item	Details
School name	St. Mary’s International School
Founded	1954, by the Brothers of Christian Instruction
Type	All-boys Catholic international school; the school states that it does not discriminate on the basis of religion or national origin in admissions
Campus	1-6-19 Seta, Setagaya-ku, Tokyo (nearest stations: Futako-Tamagawa and Kaminoge)
Grades	Readiness Program (RP, kindergarten) to Grade 12
Students (2026-27)	976 students (RP to Grade 12), 308 in High School, 43 nationalities
IB programme	Diploma Programme (DP) only; no PYP, MYP or CP (MEXT list, as of 30 June 2026)
Accreditation	WASC and CIS
Head of School	Dr Andrew Davies (2026-27 School Profile)

A small note on numbers you may see elsewhere: the school’s home page describes “close to 1,000 boys from approximately 60 different countries”, and the Tokyo Metropolitan Government’s school page gives 47 nationalities. We have used the 2026-27 School Profile figures above because they are tied to a specific school year.

How the curriculum works: only the Diploma is IB

This is the first thing to understand about St. Mary’s. St. Mary’s is authorised only for the IB Diploma Programme. Its Elementary and Middle Schools do not follow the IB PYP or MYP. Instead they use the school’s own standards-based curriculum:

Elementary School (RP to Grade 5): English language arts and maths follow the US Common Core State Standards, science follows the Next Generation Science Standards (NGSS), and social studies follows AERO standards linked to the UN Sustainable Development Goals.
Middle School (Grades 6 to 8): a standards-based curriculum developed using the Understanding by Design approach.
High School (Grades 9 to 12): every student works toward the St. Mary’s High School Diploma, and in Grades 11 and 12 nearly all students take IB courses, either as full IB Diploma candidates or through the IB Course Program.

Curriculum structure at St. Mary's International School from RP to Grade 12 — Figure 1: Curriculum structure at St. Mary’s, RP to Grade 12 (from the school website and 2026-27 Program of Studies)

Why does this matter for parents? If your child is coming from a PYP or MYP school, the move into St. Mary’s Elementary or Middle School means adjusting to a different curriculum style, even though the language of instruction is still English. On the other hand, if you want a clear route into the IB Diploma in the last two years, St. Mary’s is built around exactly that.

The High School Diploma and the IB

According to the 2026-2027 High School Program of Studies, the St. Mary’s High School Diploma requires at least 27.0 credits (30.5 recommended), including 4.0 in English, 3.0 each in maths, science, social studies and world languages, 1.0 in PE, 0.5 in the arts and 1.0 in religion or ethics. The IB Diploma is earned in addition to this school diploma.

The School Profile describes an “inclusive approach” to the IB: nearly all Grade 11 and 12 students take IB courses, and approximately 93% complete the full IB Diploma. The standard programme is three Higher Level and three Standard Level courses, and a small group of students may petition to take an additional Higher Level course, although the 2026-27 Program of Studies states that the school does not recommend taking four HL subjects. All students enrolled in IB courses sit the official external exams. The Program of Studies also notes that, from 2026, Health 9 is required for all students entering High School.

One point that often comes up: the current Program of Studies does not list Advanced Placement (AP) courses, so St. Mary’s should not be thought of as an AP school.

IB Diploma results 2024 to 2026

The 2026-27 School Profile shows three years of results. The school compares its average score with the worldwide average for each year.

Year	St. Mary’s average	Worldwide average	Highest score	Full Diploma earned	Bilingual Diploma earned
2026	35	31	45	98%	38%
2025	34	31	44	95%	40%
2024	35	30	44	100%	52%

St. Mary's IB Diploma average score compared with the worldwide average, 2024 to 2026 — Figure 2: St. Mary’s IB Diploma average score vs worldwide average, 2024 to 2026 (from the St. Mary’s 2026-27 School Profile)

The profile also reports the share of students scoring above the world average: 77% in 2026, 70% in 2025 and 77% in 2024. It does not give the number of candidates each year, so please keep in mind that percentages from a single graduating class can move noticeably from year to year. Note also that the “Full Diploma earned” figures and the profile’s statement that about 93% of students complete the full Diploma measure different things, and the profile does not define the denominators.

University destinations

For the class of 2026, the School Profile shows destinations by region: the United States 26%, Japan 20%, Asia 15%, Europe 11%, Canada 10%, the UK 8% and Oceania 8% (these shares add up to 98% as shown). Its matriculation list for the classes of 2022 to 2026 includes, for example, the University of Tokyo, Waseda, Keio, Sophia and ICU in Japan; UC Berkeley, UCLA, the University of Michigan and the University of Pennsylvania in the US; the University of Toronto and UBC in Canada; Cambridge, Imperial College London, King’s College London and UCL in the UK; and the National University of Singapore and the University of Hong Kong in Asia. University counselling begins in Grade 10, starting with an introduction to the PSAT.

Tuition and fees for 2026-2027

Let’s look at the costs honestly, because they are an important part of the decision. These are the figures on the St. Mary’s Tuition & Fees page for the 2026-2027 school year; the school notes that tuition and fees are subject to change.

Fee (2026-2027)	Amount (JPY)
Application fee (per application, non-refundable)	¥50,000
Registration (one-time, non-refundable)	¥400,000
Development Fund (one-time, non-refundable)	¥1,000,000
Building Maintenance (annual, non-refundable)	¥200,000
Tuition: Elementary School	¥2,860,000
Tuition: Middle School	¥2,970,000
Tuition: High School	¥3,050,000
School bus (optional): one way / both ways	¥310,000 / ¥420,000

St. Mary's first-year costs by school division, 2026-2027 — Figure 3: First-year costs for new students by division, 2026-2027 (tuition + Building Maintenance + one-time fees; from the St. Mary’s Tuition & Fees page)

Adding these up, a new student pays ¥1,450,000 in one-time fees (application, registration and Development Fund). The first year therefore comes to ¥4,510,000 in Elementary School, ¥4,620,000 in Middle School and ¥4,700,000 in High School, before the bus and other items. From the second year, the ongoing cost is tuition plus Building Maintenance: ¥3,060,000, ¥3,170,000 and ¥3,250,000 respectively at 2026-27 rates.

Other charges listed on the same page:

An iPad and cover for all Grade 3 boys and new Grade 4 and 5 students, and a MacBook Neo for Grade 6 and new Grade 7 and 8 students; the page does not state the prices, which are added to the school invoice.
IB exam fees of ¥20,000 per subject, billed in December for students who register for IB exams.
A Graduation Fee of ¥30,000 for all Grade 12 students (cap and gown, reception and related costs).
Trips such as the Grade 4 and 5 ski trip, Middle School field trips and the High School retreat, with details provided beforehand.
For returning families, a ¥300,000 Re-Enrollment Seat Deposit, which is credited towards tuition.

All fees except the application fee are paid by bank transfer. If your employer supports education costs, the page also mentions a Corporate Contribution Program and asks families to contact the Accounting Office for information.

Admissions: timing, age and English

When can you apply?

St. Mary’s accepts applications all year round, depending on seat availability, with some important exceptions:

The Readiness Program (RP) and Grade 1 have their own application calendar (see below).
RP applications are not accepted for enrolment later than the start of the second semester in January.
Applications are not accepted for Grade 12. To complete the IB Diploma, students must enrol no later than the beginning of Grade 11 and complete their last two full years at St. Mary’s.

For the 2026-27 school year, RP and Grade 1 places were already closed to local applicants at the time of writing, although the school was still accepting applications from families living overseas.

St. Mary's RP and Grade 1 admissions timeline for 2027-2028 — Figure 4: RP and Grade 1 admissions timeline for the 2027-2028 school year (from the St. Mary’s RP / Grade 1 Admissions page)

For entry in the 2027-2028 school year, the RP and Grade 1 calendar is as follows. Applications open on 1 September 2026 and close on 31 October 2026, and teacher recommendations are due by 20 November 2026. For RP, there is an on-campus group observation on 9 January 2027, family interviews between 18 January and 12 February 2027, and decision letters on 28 February 2027. For Grade 1, there is on-campus screening on 3 to 6 November 2026, a group observation on 14 November, family interviews between 30 November and 11 December 2026, and decision letters on 31 January 2027. After an offer, the registration fee and Development Fund are due within two weeks.

Age and grade placement

Boys are placed with their age-level peers and must be the right age for the grade by 1 September. They must also have completed a full year of the grade before the one they are applying for.

Applicant prerequisites

The admissions policy lists several prerequisites. The applicant should be an English-speaking student from an accredited school in which English is the medium of instruction; provide two years of school records with no indication of academic concerns, or current standardised testing in the average to above-average range; have received no special educational services; and submit all required documents and the application fee. The admissions page adds that students are admitted on the basis of previous school transcripts, standardised test results, a screening test and a personal interview with the prospective student and parents.

English requirements and support

This is where planning ahead really matters. The admissions policy says applicants should show the potential to succeed in an English-based curriculum, and it is specific about support:

English language support is offered from RP through Grade 8.
Support is only limited for students entering Grades 9 or 10.
There is no English language support for students entering Grade 11, because of the demands of the IB Diploma.

In practice, this means that if your son is still building his English, the earlier he joins, the more support is available. The policy also says that, for students with limited English proficiency, priority is given to those who have no other educational options locally. Separately from English language support, the Student Support Services team runs academic support classes that reinforce the mainstream curriculum for Grades 6 to 12.

What you will need

Families submit an application form, a confidential information form and a record release form, a birth certificate or passport page showing the date of birth in English, a recent family photo, school records from at least the last two years and the current year’s progress report. Recommendations vary by grade: a kindergarten teacher’s recommendation for RP and Grade 1, an elementary teacher’s recommendation and a counsellor or principal reference for Grades 2 to 5, and English and mathematics teacher recommendations plus a counsellor or principal reference for Grades 6 to 8. High School applicants (Grades 9 to 11, since Grade 12 applications are not accepted) provide an official transcript and school profile, a standardised test score report (such as IOWA, SSAT or PSAT), a counsellor or principal reference, and recommendations from their mathematics and English teachers.

Faith, learning support and student life

Catholic identity. St. Mary’s describes itself as an all-boys Catholic international school that embraces diversity, and the Tokyo Metropolitan Government’s school page describes it as welcoming boys of all faiths. Religion or ethics is part of the curriculum: in High School, students need 1.0 credit in religion or ethics, with courses such as Introduction to Catholicism and Business Ethics. Mass is held in the school chapel on weekday mornings. The admissions policy lists Catholic students among the groups given priority, alongside brothers of current students, children of alumni, and children of faculty and administration.

Learning support. Learning Support Coordinators help boys who are not performing at grade level. The school is open about its limits: it states that it does not have the facilities or resources to serve children with serious learning, emotional or physical disabilities, so please discuss any needs frankly during admissions.

Arts and sports. Music is a strong tradition, with 14 music groups including internationally known choirs, and the school says more than 90% of High School students take part in the arts. In sport, St. Mary’s has nearly 40 teams competing in the Kanto Plain Association of Secondary Schools (KPASS), from wrestling and rugby to swimming. The Tokyo Metropolitan Government’s page lists facilities including a 25-metre swimming pool, gymnasium, tennis courts, soccer field and theatre.

Japanese. Japanese is taught from Grade 2 to Grade 5 at three levels, and in High School the options lead to IB Japanese A: Language and Literature, IB Japanese B or IB Japanese ab initio.

The school day. Classes run from 8:30 to 15:10 in Elementary, 8:25 to 15:15 in Middle School and 8:25 to 15:25 in High School. The 2026-27 school year begins in late August (24 August 2026 for Grades 3 to 12) and ends on 11 June 2027.

Questions parents often ask

Do we need to be Catholic?

No. The school states that it does not discriminate on the basis of religion, and it describes itself as welcoming students of all faiths. Catholic students are one of several priority groups in admissions, and all students take religion or ethics courses, so it is worth thinking about how your family feels about that.

My son is coming from a PYP or MYP school. Will that be a problem?

It is not a barrier, but the curriculum below Grade 11 is not IB at St. Mary’s, so expect a different style of units and assessment. Ask the school how it helps students transition, especially in Middle School.

Can my son join in Grade 11 or 12?

Grade 11 is the last point of entry if he wants to complete the IB Diploma, and there is no English language support for students entering Grade 11. The school does not accept applications for Grade 12.

We are a Japanese family. Can our son apply?

Possibly, but read the conditions carefully. St. Mary’s is not an “Article 1” school under Japan’s School Education Law, and the admissions policy asks Japanese parents to consider the legal implications for compulsory education (Grades 1 to 9) before applying. The school may consider Japanese citizens who meet the academic requirements if the child’s most recent education was in an English-medium school (for at least a year in elementary or middle school, or two years in high school), or if a parent is an English-speaking expatriate.

Is there a school bus?

Yes. The 2026-27 price is ¥310,000 a year one way or ¥420,000 for both ways. Ask the school about routes near your home.

Summary

All-boys Catholic school, founded in 1954: 976 students from 43 nationalities in 2026-27, and the school states that it welcomes families of all faiths.
IB Diploma only: Elementary and Middle School use the school’s own standards-based curriculum; nearly all Grade 11 and 12 students take IB courses and about 93% complete the full Diploma.
Results: an average of 35 points in 2026 against a worldwide average of 31, with 98% earning the full Diploma.
2026-27 fees: tuition from ¥2,860,000 (Elementary) to ¥3,050,000 (High School), plus ¥200,000 Building Maintenance each year and ¥1,450,000 in one-time fees.
Plan ahead for English and entry points: English support runs from RP to Grade 8, Grade 11 is the last entry point for the IB Diploma, and RP and Grade 1 have a fixed autumn application calendar.

If St. Mary’s sounds right for your son, the best next step is to contact the admissions office and, if you are aiming for RP or Grade 1 in 2027-28, to note the 31 October 2026 application deadline.