School accreditation explained: CIS, WASC, NEASC, IB — and why membership isn't accreditation
Four different things hide behind the logos on school websites. This guide separates them, and shows how to verify any claim in five minutes. Based on CredRadar's methodology research, 2026-10-06.
The four categories — at a glance
CredRadar records accreditation only where a source names it; see /methodology/.
1 · Four things that are not the same thing
Licence. Every legal international school in Thailand operates under a Ministry of Education (OPEC) licence. It proves the school may operate — nothing about quality. Accreditation is a cyclical, whole-school external evaluation by an independent body. Authorisation is programme-specific permission (to teach the IB Diploma, to examine Cambridge IGCSEs, to run AP courses). Membership is joining an association — valuable for networks and sports leagues, but no inspection stands behind it. School marketing routinely lists all four side by side; parents should not.
2 · The accreditors you will meet in Thailand
| Body | Type | Notes |
|---|---|---|
| CIS (Council of International Schools) | Accreditation | The most common international accreditation in Thailand; often held jointly with a US accreditor. |
| WASC | Accreditation | US-based; common for American-curriculum schools. Full accreditation follows candidacy — check which stage. |
| NEASC | Accreditation | US (New England) accreditor, frequently paired with CIS. |
| Cognia | Accreditation | US accreditor (formerly AdvancED); common among smaller American-model schools. |
| BSO / EDT | Inspection | British Schools Overseas inspections (delivered by EDT and others) — the UK government's framework for British schools abroad. |
| ONESQA | Thai state QA | Thailand's own external quality assessment, required domestically; distinct from international accreditation. |
3 · Authorisations: IB, Cambridge, College Board
An "IB World School" is authorised per programme — PYP, MYP, DP and CP are separate authorisations, and a school authorised for PYP only is not an IB Diploma school. Cambridge and Pearson Edexcel authorise exam centres for IGCSE/A Level; the College Board authorises AP courses school by school. When CredRadar's dataset says a school offers a programme, it reflects what a source states — the authorising body's own directory is the final word.
4 · Memberships — useful, but different
ISAT (the Thai association), FOBISIA and COBIS (British-international federations) and EARCOS (East Asia regional council) are membership networks. They run conferences, sports and professional development, and most good schools belong to at least one. But membership involves no whole-school inspection cycle, and presenting it as accreditation is the single most common piece of quality-marketing inflation in this sector.
5 · Verify any school in five minutes
- IB claims: search the school on ibo.org — the IB's own finder lists exactly which programmes are authorised.
- CIS / WASC / NEASC / Cognia: check the accreditor's member/accredited directory, and note whether the status is full accreditation or candidacy.
- Licence & local standing: check the school's entry in the ISAT directory (isat.or.th/search) and ask the school for its OPEC licence and latest ONESQA report.
- Fees: download the current-year fee PDF from the school's own site before relying on any third-party figure — including ours, which is why every CredRadar fee carries an [O]/[A]/[NV] label.
6 · Red flags
- A wall of association logos, but no named accreditor or inspection date.
- "IB school" marketing from a school that appears on ibo.org as a candidate — or not at all.
- An "American diploma" with no US accreditor behind the school.
- Fees available only after a sales conversation, with no published schedule.
- Accreditation claims that name a body whose directory doesn't list the school.
7 · FAQ
Is ISAT membership a quality guarantee?
No. ISAT is the Thai international schools' association — a membership body. Membership says a school belongs to the sector's network; it is not an inspection or accreditation. The same applies to FOBISIA, COBIS and EARCOS membership.
What is the strongest signal a school is properly accredited?
A current accreditation from CIS, WASC, NEASC or Cognia (or a BSO inspection for British schools), verifiable in the accreditor's own directory — plus, for IB schools, authorisation for the specific programmes it advertises, verifiable on ibo.org.
A school says it is an 'IB candidate school'. What does that mean?
It is in the authorisation process and may not yet offer the IB programme it is candidating for. Candidate status is a legitimate stage, but it is not authorisation — ask which programmes are authorised today, and verify on ibo.org.
Does accreditation affect university recognition of the diploma?
Universities read the qualification (IB Diploma, A Levels, AP, a diploma from an accredited school). An unaccredited 'American diploma' is the weak point to probe: accreditation is what makes a school-issued diploma portable.
See also: Fees guide · Curriculum guide · Methodology