St. Mary's International School: The Discipline and University Success of Tokyo's All-Boys International School

St. Mary's International School, located in Seta, Setagaya-ku, Tokyo, is the only all-boys international school in the Tokyo area.

"An all-boys international school? Is it as strict as a traditional Japanese private boys' school?"

"Is it all about sports, or are academics strong too?"

In a world where co-educational schools are the norm for international education, St. Mary's stands out. However, it's far from being a 'Spartan' sports-focused institution.

It is a highly logical, university-preparatory school that successfully combines 'Boy-Friendly' education tailored to the developmental characteristics of boys with 'IB results that significantly exceed the global average'.

In this article, we provide a comprehensive analysis of the prestigious 70-year-old St. Mary's, covering its educational features, specific admission details, tuition fees, and what parents are most curious about—the benefits of an all-boys international school—based on the latest information for 2026.

1. Why an All-Boys School Now? The Strengths of St. Mary's

When compared to co-educational schools like the American School in Japan (ASIJ) or the British School, the most significant difference is, of course, the all-boys environment. However, this is not merely a tradition.

Boy-Friendly Education

St. Mary's places the principle that 'boys thrive on competition and learn by doing' at the core of its curriculum design. Instead of lessons that require sitting still and listening quietly, the school frequently incorporates activities that engage the hands and body, such as gamified tasks, fieldwork, and robotics, to maximize boys' concentration.

Freedom to Pursue the Arts Without Social Pressure

In co-ed schools, some boys might shy away from activities like choir or drama, viewing them as 'for girls.' That's not the case here. There is a culture where 'it's cool to be smart/artistic' and to immerse yourself in something without worrying about the judgment of the opposite sex. As a result, many students participate in the world-renowned Choir and take part in serious musical theater productions.

A Strong Sense of Brotherhood

Students from ages 5 to 18 share the same campus. Through programs like the 'Big Brother' system, high school students regularly have opportunities to look after elementary schoolers, fostering a sense of brotherhood that transcends age groups. This is a unique appeal of an all-through, all-boys school.

2. A Balance of Academics and Athletics? Impressive IB Scores and University Placements

While it may have a strong image as a 'sports school,' St. Mary's also boasts some of the top academic results in Tokyo.

IB Diploma Results (Far Exceeding the Global Average)

The high school (Grades 11-12) follows the International Baccalaureate (IB DP) curriculum, and its results are outstanding.

• Pass Rate: Consistently over 90%, with a 100% pass rate among all candidates in 2022.
• Average Score: While the world average is around 30 points, St. Mary's consistently achieves an average of 35-37 points.

An All-Boys School with Strengths in STEM

Particularly noteworthy are its strengths in Math and Science. In the 2020 IB exams, the average score for Physics HL (High Level) was 6.36 (world average 5.29), and Math HL was 6.09 (world average 5.05), significantly outpacing global averages in STEM subjects. An environment where students are exposed to robotics and coding from elementary school helps cultivate this aptitude for STEM.

University Placements (To Top Universities in Japan, the US, and Europe)

Many graduates go on to attend prestigious universities around the world.

• International: Numerous acceptances to the world's most selective universities, including Harvard, Yale, MIT, Stanford, and Oxford. The school has a particular strength in placements for medical and engineering programs abroad.
• Domestic: Consistent placements at top Japanese universities such as Waseda University (SILS), Keio University (PEARL/GIGA), Sophia University, and ICU.

3. Admissions Schedule and Process (First Year vs. Transfer)

The admissions process at St. Mary's varies depending on the grade level.

Grade 1 Admissions Process

Applying for Grade 1 is the most popular route with the highest number of available spots.

1. Application (Autumn): Submit applications between early September and late October of the year before entry.
2. Written Screening (Early November): A 30-minute test on an iPad, similar to the MAP test format, assessing math concepts and English listening skills.
3. Group Observation (Mid-November): A group observation session where children's cooperation and ability to follow instructions are assessed through activities like playing with blocks and drawing.
4. Parent-Child Interview (Early December): An interview in English with the Head of School. The focus is on whether the parents' educational philosophy aligns with the school's mission (including its Catholic values and approach to boys' education).
5. Notification of Results: Sent out at the end of January.

The Reality of Mid-Year Transfers

Admissions for Grade 2 and above are on a 'Rolling Admissions' basis.

• Assessment: Includes a MAP test (Math and English Reading) for academic diagnosis, an English essay, and an interview.
• EAL (English as an Additional Language) Limitations: This is a key point. EAL support is generally available only up to Grade 8.
• The High School Barrier: Support in Grades 9-10 is limited, and there is no EAL support for students entering Grade 11, when the IB Diploma Programme begins. Near-native English proficiency is required for admission to the upper grades.

4. Legendary Extracurriculars and School Culture

No discussion of St. Mary's is complete without mentioning its vibrant extracurricular activities and disciplined school culture.

The Pride of the 'Titans': Sports and Music

• Wrestling: A legend in the international school community. The team is a dominant force, having won the Kanto Plain and Far East tournaments more than 20 times.
• Men's Choir: It's not just sports; music is also first-class. The choir is a powerhouse that has won gold medals in international competitions, and the sound of 100 boys singing together is breathtaking.
• Debate Club: Often recognized as one of the best in Japan, where students compete to hone their logical thinking skills.

Discipline and the Catholic Spirit

Although it is a Catholic mission school, it does not compel students to practice the faith. However, ethical values such as 'service to others' and 'integrity' are strongly emphasized. Furthermore, a uniform with a blazer and tie is mandatory. Compared to more liberal schools like YIS (Yokohama International School), St. Mary's is stricter about appearance and etiquette, aiming to cultivate 'Gentlemen'.

5. Tuition and Fees (2025-2026 Estimates)

The fees are within the standard range for a top-tier international school in Tokyo, but significant one-time payments are required in the first year.

Estimated First-Year Total Cost: Approx. ¥4,500,000 - ¥4,800,000

(Includes tuition, one-time fees, bus, uniform, PC, etc.)

Conclusion: What Kind of Student is St. Mary's a Good Fit For?

St. Mary's International School offers children more than just an 'English-speaking environment'.

This school is a good fit for families who:

• Want their son to grow up to be resilient and well-mannered.
• Have a son who is interested in or wants to develop skills in STEM or robotics.
• Want their son to experience dedicating himself seriously to something, whether it's sports, music, or another passion.
• Feel more comfortable with a certain level of discipline (uniforms, school rules) rather than an overly liberal environment.

For adolescent boys, the 'all-boys' environment can be a 'safe haven' where they can express themselves fully without unnecessary social pressure.

If your son is an active learner who thrives on friendly competition with his peers, St. Mary's could be the perfect choice.

Check the Official Website for Open House Information