Thailand's securities regulator requires listed companies to report under the global climate reporting standards (IFRS S1 and IFRS S2) in their annual report, starting with their own emissions (Scope 1 and Scope 2), checked by an independent verifier.
The 50 largest companies start collecting data in 2027 and publish in 2028; the next 50 follow a year later, all other main-board companies from 2029, and smaller-market companies, trusts and funds from 2030.
The first group is the SET50 index as it stands after its December 2026 review.
Supply-chain emissions (Scope 3) join after five years, so the first task is an inventory of the company's own emissions.
| Regulator | Securities and Exchange Commission, Thailand, with revised principles approved by the Capital Market Supervisory Board in November 2025. Disclosure sits in the annual report (Form 56-1 One Report) |
| Standard | IFRS S1 and IFRS S2, climate first: the climate parts of IFRS S1 plus all of IFRS S2 during a five-year transition |
| Companies in scope | Thai and foreign companies listed on the Stock Exchange of Thailand (including companies listing for the first time), then companies on the Market for Alternative Investment (mai), listed real estate investment trusts, infrastructure trusts, property funds and infrastructure funds, phased in by index membership |
| Estimated population | 50 companies in the first wave (the SET50 index at its December 2026 review) and 100 in the second (the SET100 index at its December 2027 review). Later waves: Not yet published |
| First reporting year | 2027 for SET50 companies, with first reports in 2028 (regulator's table: effective timeline 2027, reporting period 2028) |
| Scope 3 required | Yes, after a five-year transition during which companies report Scope 1 and Scope 2 only |
| Assurance | Independent check of greenhouse gas emissions from the first report, by a verifier registered with the Thailand Greenhouse Gas Management Organization or one applying international assurance standards. Limited assurance, per the IFRS Foundation's Thailand profile. Reasonable assurance: Not specified in the rule |
| Penalty regime | Not specified in the rule |
Thailand's Securities and Exchange Commission confirmed on 28 November 2025 that companies listed on the Stock Exchange of Thailand will report under IFRS S1 and IFRS S2, starting with independently checked Scope 1 and Scope 2 emissions: the 50 largest companies from 2027 with first reports in 2028, and every listed company, trust and fund reporting by 2031. Thailand joins Singapore, Malaysia, Hong Kong, Japan and Australia in building its rules on the global IFRS sustainability standards.
Companies in scope report climate-related risks, opportunities and greenhouse gas emissions under IFRS S2, applying the general requirements of IFRS S1, in the annual Form 56-1 One Report.
IFRS S1 (General Requirements): sets the reporting entity, the materiality test and where disclosures sit, applied to climate information only during the five-year transition.
IFRS S2 (Climate-related Disclosures): applied in full. It follows the four-pillar structure of governance, strategy, risk management, and metrics and targets, and requires Scope 1, Scope 2 and Scope 3 emissions, with Scope 3 deferred for five years.
Checked emissions data: the Commission's November 2025 announcement names Scope 1 and Scope 2 disclosure "accompanied by standardized and reliable assurance" as the core of the first phase.
The GHG Protocol as the measurement standard: IFRS S2 paragraph 29(a)(ii) requires measurement under the Greenhouse Gas Protocol Corporate Accounting and Reporting Standard (2004). The Commission allows an equivalent international method for the first five years.
Transition reliefs in the Commission's roadmap: no prior-year comparison in the first report; five years of climate-only reporting; five years to publish separately from the annual accounts; five years of flexibility on the measurement method; and five years without Scope 3.
Current rules: since 2022, every listed company has reported sustainability information in the 56-1 One Report, explaining any gaps. The new rules replace that with compulsory reporting under IFRS S1 and IFRS S2, wave by wave.
The rules cover every company with securities listed in Thailand, phased in by market and index membership.
The mandate applies to Thai and foreign companies listed on the Stock Exchange of Thailand (primary, secondary and dual listings), companies listing for the first time, and listed real estate investment trusts, infrastructure trusts, property funds and infrastructure funds. Companies on LiVEx, the exchange's start-up market, are outside the mandate.
Listed companies, four waves
Wave 1, SET50: companies in the SET50 index after its December 2026 review. Effective 2027, first reports 2028.
Wave 2, SET100: companies in the SET100 index after its December 2027 review. Effective 2028, first reports 2029.
Wave 3, all main-board companies: every other company on the Stock Exchange of Thailand, including new listings. Effective 2029, first reports 2030.
Wave 4, smaller-market companies, trusts and funds: companies on the Market for Alternative Investment, plus listed real estate investment trusts, infrastructure trusts, property funds and infrastructure funds, including new listings. Effective 2030, first reports 2031.
Supply-chain reach (Terrascope analysis): the first two waves cover Thailand's largest energy, petrochemical, food, retail and financial groups. When the Scope 3 relief ends, they need supplier emissions data, so agricultural producers, food processors, packaging makers, logistics providers and contract manufacturers across Southeast Asia should expect Scope 3 data requests from Thai customers.
| Milestone | Measurement year | First reporting date |
| Sustainability reporting in the 56-1 One Report, explain any gaps | Current rules | Since 2022 |
| Public consultation on the roadmap | 19 November to 19 December 2024 | Closed |
| Revised principles approved by the Capital Market Supervisory Board | November 2025 | Announced 28 November 2025 |
| Wave 1: SET50 | 2027 | 2028 |
| Wave 2: SET100 | 2028 | 2029 |
| Wave 3: all main-board companies | 2029 | 2030 |
| Wave 4: smaller-market companies, trusts and funds | 2030 | 2031 |
| Scope 3 reporting | After five years of reporting | After five years of reporting |
The Commission is amending the underlying regulations and the 56-1 One Report form.
1. Supply-chain ripple across Southeast Asia. Thailand's listed groups buy agricultural commodities, packaging, components and logistics across the region. Once the Scope 3 relief ends, supplier engagement becomes part of the annual reporting cycle.
2. Regional convergence on IFRS S2. Thailand adopts IFRS S1 and IFRS S2 directly, alongside Singapore, Malaysia, Hong Kong, Japan and Australia. A corporate carbon footprint measured once on the GHG Protocol serves each of these regimes.
3. A domestic verification route. Thailand accepts verifiers registered with the Thailand Greenhouse Gas Management Organization alongside verifiers applying international assurance standards. Companies already verified under the agency's carbon footprint programmes have a head start on the first checked report.
The SET50 list is fixed after its December 2026 review and the first reporting year is 2027, so calendar-year companies need their inventory running from 1 January 2027.
Establish your greenhouse gas inventory on the GHG Protocol. Scope 1 and Scope 2 across the consolidated group is the year-one deliverable.
Map your value-chain exposure to Thai reporting companies. Scope 3 arrives after five years of reporting. Use that window to find your largest supplier categories.
Build assurance-ready processes early. Verification applies from the first report, so methodology documentation, source-data traceability and review controls have to exist from the first inventory. A verifier asks "where did this number come from?" for every figure.
Build on the frameworks you already use. Your current 56-1 One Report sustainability section, carbon footprint work with the national greenhouse gas agency and CDP responses all rest on the same inventory, and IFRS S2 keeps the four-pillar structure you already report against.
Terrascope's AI-powered platform helps companies operating across Asia move from baseline emissions data to audit-ready disclosures, including Banyan Group, which measured Scope 1, 2 and 3 emissions across 76 entities in 14 countries, turning over 130,000 business activities into emissions data in weeks.
Scope 1, 2, and 3 emissions measurement. Integrations pull emissions data from your source systems monthly, and Data in Any Format handles the spreadsheets and offline records, so your inventory covers every entity in the consolidated group.
Audit-ready reporting. Audit Trail makes every figure traceable from data entry to disclosure, with verifier access built in, so the first checked report runs on evidence that already exists.
Supply-chain intelligence. Analytics shows you where your Scope 3 hotspots sit before the relief ends, so the five years become reduction planning time.
Multi-framework alignment. Climate Reporting drafts your IFRS S2 disclosures from your measured data, reviewed by your team, ready for the 56-1 One Report.
Are you ready to get ahead of Thailand's IFRS S2 requirements? Speak to a Terrascope expert and see how we help companies move from baseline emissions data to audit-ready disclosures.