Founded
1992

Established with United Nations support

Curriculum
Full IB continuum

PYP + MYP + DP; Thailand’s first full IB school

Years
EY–13

Ages 3–18; 1,800+ students, 77+ nationalities

Location
Sukhumvit Soi 15

Minutes from Asok BTS and Sukhumvit MRT

Structure
Not-for-profit

Parent-elected foundation; CIS + NEASC + ONESQA

Tuition 2025/26
THB 628,200–1,094,500

Plus THB 265,000 registration + deposit choice

The short version

The short version

NIST International School is a not-for-profit, full IB continuum school founded in 1992 with the support of the United Nations — the first full IB World School in Thailand, offering all three programmes by 1999.

It teaches over 1,800 students from Early Years to Year 13 on a 25-rai campus at 36 Sukhumvit Soi 15, a short walk from Asok BTS, and describes its community of 77-plus nationalities as the most diverse of any international school in Thailand.↗↗

For an expat family, the practical summary is this: NIST is the IB answer in central Bangkok — a coherent 3-to-18 pathway, published results well above world averages, and the only tier-one school you can genuinely walk to from Sukhumvit condos.

The cost is the market’s highest first-year outlay once the registration fee and campus development choice are added, and Year 7 and Year 12 entry is tight. Plan early, and do the deposit maths before signing.

What the school is

A parent-governed foundation with a UN founding story

NIST’s governance is its quiet differentiator. The school is not-for-profit and governed by the parent-elected NIST International School Foundation — the parent body has a direct electoral line into decisions on buildings, staffing and fees — and the school states that all fee income is invested back into operations and campus improvement.

In a market where most premium schools answer to owners or licensors, this is a structurally different accountability.↗

The accreditation record matches the founding ambition: NIST was the first school in Thailand to hold triple accreditation from CIS, NEASC and ONESQA — satisfying Thailand’s legal requirement for recognised overseas accreditation several times over.

The UN relationship persists in practice rather than just history: the service programme is aligned directly with the UN Sustainable Development Goals and woven into the curriculum.↗↗

One credential most parents have never heard of: NIST belongs to a nine-school consortium offering the Global Citizen Diploma, a qualitative credential that lets students document global-citizenship learning alongside the IB Diploma and the NIST High School Diploma. Ask how universities receive it — it is a differentiator in applications that value more than points.↗

Academics in practice

Published results: three perfect scores and a 36.1 five-year average

NIST publishes its outcomes at cohort level. In 2025, 110 IB Diplomas were awarded from a cohort of 118; three students scored a perfect 45; 27% scored 40 or above against a worldwide average of 9%; and 62% graduated with a bilingual diploma.

The five-year Diploma average stands at 36.1 points against a global 30.2.↗↗

The continuum is the pedagogical point: PYP inquiry becomes MYP discipline becomes DP specialisation without a curriculum switch at 11 or 16.

For children arriving from non-IB systems, the school integrates English support through the PYP and MYP — and, unusually, charges no extra fee for EAL, where several Bangkok peers bill six figures for it.↗

The honest caveat is cohort context: 110–120 DP students a year is a large, meaningful cohort by IB standards, but read any single year’s average against the five-year trend the school itself publishes. And if your child wants A-levels or AP, NIST offers neither — the IB is the whole model.

Fees and the real cost

The THB 575,000 deposit choice — and how to run the maths

NIST’s 2025/26 tuition, as quoted by Thailand’s Board of Investment from the school’s schedule, runs from THB 628,200 in Early Years through THB 842,800 in Years 2–6 and THB 923,700 in Years 7–9 to THB 1,094,500 in Years 12–13.

The 2026/27 figures captured from a fees aggregator run from THB 650,200 to THB 1,132,800 — confirm the current cycle with admissions before budgeting.↗↗

The one-time charges are a THB 6,000 application fee, a THB 2,500 non-refundable assessment fee and a THB 265,000 non-refundable registration fee.

Then comes the choice that defines year one: a THB 575,000 refundable Campus Development Deposit — refunded within 45 days of withdrawal, less outstanding bills — or a THB 60,500 annual non-refundable Campus Development Fund payment.↗↗

The break-even is arithmetic every family should do: THB 575,000 divided by THB 60,500 is about nine and a half years, so the deposit only “wins” financially on very long enrolments — but it is refundable capital, not a cost, if you trust the refund process and have the cash.

A three-year posting points to the annual fund; a settle-in-Bangkok family with two children should price both routes. Either way, a first year for a three-year-old totals roughly THB 1.5 million all-in — the highest entry cost among Bangkok’s leading schools.↗

Admissions

Assessment-based entry in a compact school

Admission runs through age-appropriate assessment in English and mathematics, with MYP and DP candidates also reviewed on prior school reports.

NIST is the smallest of Bangkok’s tier-one trio by campus footprint, and secondary sources consistently flag Year 7 and Year 12 as the tightest entry points — ask for the honest position in your child’s year group before building the move around NIST.↗

The diversity cuts both ways for planning: with 77-plus nationalities and heavy turnover among internationally mobile families, places do open mid-year — but the same turnover means demand recycles constantly. Families posted on corporate cycles should engage admissions as soon as the posting is confirmed, not on arrival.

The family experience

The urban option: Sukhumvit life without the school-run

NIST’s location is its lifestyle proposition. The 25-rai, ten-building campus sits minutes from Asok BTS and Sukhumvit MRT in the middle of the city’s business and condo district — the only tier-one Bangkok school where a central-Sukhumvit family can realistically walk or take one train stop to school.

A 2025 building programme added Innovation, Pavilion and new Elementary buildings to ease the squeeze of a compact urban site.↗↗

The trade-off is the inverse of ISB’s or Patana’s: no sprawling playing fields next door, a dense campus rhythm, and a community skewed toward families who have chosen city life deliberately.

Parents comparing the city’s leading schools describe NIST as the school for families who want walking-distance schooling and the most internationally mixed peer group in Thailand — and who have made peace with urban scale.

Our readConfidence: High

The IB school for city families — priced at the top, governed by parents

Our confidence is High: NIST publishes cohort-level results and its not-for-profit governance openly, its 2025/26 fees are on record in a Thai government publication quoting the school’s own schedule, and its triple accreditation is independently verifiable.

The open items are the current-year fee cycle and the real-world experience of the deposit refund — policy says 45 days; ask parents who have withdrawn how it actually went.

The families NIST suits: IB-committed families who want one philosophy from age 3 to 18, city families for whom the Sukhumvit location removes the school run, and internationally mixed communities where no nationality dominates.

The families it suits less well: those wanting A-levels or AP, those needing large-campus sport at the doorstep, and cash-flow-sensitive families for whom THB 575,000 of locked-up deposit — or the market’s highest first-year bill — is a constraint. Do the deposit maths, then visit.

Take these to the school

Questions that move beyond the tour script

Admissions and transition

  1. For our child’s year group and entry date, what is the realistic position — offer, waitpool, or a later cycle?
  2. What does the assessment involve at our child’s age, and how are children from non-IB curricula supported in year one?
  3. How is EAL need assessed, given it carries no extra fee — is provision capped?

Academics and pathways

  1. May we see the full IB Diploma results for the last three cohorts, with subject-level detail for our child’s intended HL courses?
  2. How does the Global Citizen Diploma appear on transcripts, and which universities have responded to it?
  3. How is service learning assessed within the curriculum rather than added on?

Cost and the deposit

  1. What are the confirmed 2026/27 fees and one-time charges for our child’s year group?
  2. How does the Campus Development Deposit refund work in practice — timeline, deductions, and what families should document?
  3. Beyond tuition and the deposit choice, what should we budget for trips, devices, lunch and activities in year one?

Continue your research

Choose your next step

Sources and further research

Where to verify and keep reading

We favor direct links to the exact page or document a family may need next. Access dates matter because admissions, tuition, leadership, and programs change.