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ISSB Adoption Tracker: Which Countries Are Implementing IFRS S1 and S2?
When the International Sustainability Standards Board (ISSB) published IFRS S1 (General Requirements for Disclosure of Sustainability-related Financial Information) and IFRS S2 (Climate-related Disclosures) in June 2023, it marked the beginning of a new era in sustainability reporting. For the first time, a single global baseline existed for investor-focused sustainability disclosure, built on the foundations of the TCFD, SASB, and IIRC frameworks that the IFRS Foundation absorbed.
Nearly three years later, the picture is no longer theoretical. Countries are legislating. Regulators are issuing timelines. Companies are building compliance programs. But adoption is far from uniform — the approaches range from full mandatory implementation to voluntary encouragement, with significant variation in scope, timing, and local modifications.
For CSOs, sustainability managers, and compliance teams at multinational companies, understanding which jurisdictions have adopted ISSB standards (and how) is no longer optional. It is the foundation of any credible multi-framework reporting strategy.
This article provides a comprehensive, country-by-country overview of ISSB adoption as of early 2026, explains the key differences in implementation approaches, addresses the critical question of ISSB-ESRS interoperability, and outlines what companies should do to prepare.
The Global Adoption Landscape at a Glance
ISSB adoption falls into several distinct categories. Some jurisdictions have mandated IFRS S1 and S2 directly or through locally aligned standards. Others have adopted them on a voluntary or comply-or-explain basis. A significant group is actively considering adoption with formal consultations underway. And one major bloc — the European Union — has developed its own parallel framework while working on interoperability.
The following table summarizes the status across key jurisdictions.
Country-by-Country Adoption Status
| Country/Region | Status | Standard Used | Mandatory Start | Scope | Key Details |
|---|---|---|---|---|---|
| United Kingdom | Mandatory (phased) | UK SRS (ISSB-aligned) | FY 2025 (largest companies) | Large listed companies, then expanding | UK Sustainability Reporting Standards endorsed by FCA; phased rollout beginning with FTSE 100 and large PIEs |
| Japan | Mandatory (phased) | SSBJ Standards (ISSB-aligned) | FY 2027 (first wave) | Listed companies by market cap tiers | SSBJ finalized standards aligned with IFRS S1/S2; first wave targets companies with market cap above JPY 3 trillion |
| Australia | Mandatory | AASB S1/S2 (ISSB-aligned) | FY 2024-25 (Group 1) | Phased by entity size | AASB adopted ISSB-aligned standards; Group 1 (large entities) reporting from 2024-25, Group 2 from 2026-27, Group 3 from 2027-28 |
| Singapore | Mandatory | ISSB-aligned (SGX rules) | FY 2025 | SGX-listed companies | SGX mandated ISSB-aligned climate reporting for all listed companies; phased by industry |
| Hong Kong | Mandatory | HKFRS S1/S2 (ISSB-aligned) | FY 2025 (Main Board) | HKEX-listed companies | HKEX adopted ISSB-aligned standards for Main Board issuers; GEM Board follows later |
| Nigeria | Mandatory | IFRS S1/S2 (direct adoption) | FY 2023-24 | Listed and significant public entities | Financial Reporting Council of Nigeria adopted ISSB standards directly; early mover |
| Turkey | Mandatory (planned) | TFRS S1/S2 (ISSB-aligned) | FY 2025 | Large PIEs, expanding | Public Oversight Authority adopted Turkish translations of ISSB; phased rollout |
| Brazil | Converging | CVM rules (ISSB-aligned) | FY 2026 (phased) | Listed companies | CVM issued resolution requiring ISSB-aligned climate reporting; phased by company size |
| Canada | Voluntary / under review | CSSB Standards (ISSB-based) | TBD | Under consultation | Canadian Sustainability Standards Board (CSSB) issued ISSB-based exposure drafts; mandatory adoption timeline not yet confirmed |
| South Korea | Voluntary / planned | KSSB Standards (ISSB-aligned) | FY 2026 (voluntary), mandatory TBD | Listed companies | Korea Sustainability Standards Board established; voluntary adoption encouraged from 2026, mandatory timeline under discussion |
| Malaysia | Mandatory (phased) | Bursa Malaysia rules (ISSB-aligned) | FY 2025 (Main Market) | Bursa-listed companies | Bursa Malaysia mandated ISSB-aligned climate disclosures; phased by market segment |
| New Zealand | Mandatory (climate) | XRB NZ CS standards (TCFD/ISSB-influenced) | FY 2022-23 (in force) | Large listed entities, banks, insurers, asset managers | Climate-related disclosure regime already operational; alignment with ISSB S2 being reviewed |
| South Africa | Voluntary / planned | JSE guidance (ISSB-referenced) | TBD | JSE-listed companies | JSE issued guidance referencing ISSB; formal mandatory adoption timeline not yet set |
| Saudi Arabia | Voluntary / planned | SOCPA alignment (ISSB-based) | Under consultation | Listed and regulated entities | Saudi Organization for Chartered and Professional Accountants working on ISSB alignment |
| India | Under consideration | ISSB-referenced | TBD | TBD | SEBI and Ministry of Corporate Affairs monitoring ISSB developments; existing BRSR framework may evolve toward ISSB alignment |
| European Union | Own framework (ESRS) | ESRS (interoperability with ISSB) | FY 2024 (Wave 1) | Phased by company size | EU adopted its own ESRS under CSRD; uses double materiality vs. ISSB’s single materiality. EFRAG-ISSB interoperability guidance published |
| United States | Voluntary | No federal mandate | N/A | N/A | SEC climate rules significantly scaled back; ISSB adoption voluntary. Some states (California) have state-level disclosure laws |
Mandatory Adopters: Where ISSB Is Already Law
United Kingdom
The UK has emerged as one of the most decisive ISSB adopters among major economies. The UK Sustainability Reporting Standards (UK SRS), endorsed by the Financial Conduct Authority (FCA) and the Department for Business and Trade, are closely aligned with IFRS S1 and S2 with limited UK-specific modifications. The phased rollout starts with the largest listed companies and public interest entities for fiscal years beginning in 2025, expanding to a broader set of large companies in subsequent years.
The UK approach is notable for maintaining close alignment with the ISSB baseline while making targeted adjustments for the UK regulatory context. For multinational companies with UK-listed entities, this means ISSB-aligned reporting is now a legal requirement, not a voluntary exercise.
Australia
Australia moved quickly on ISSB adoption. The Australian Accounting Standards Board (AASB) issued AASB S1 and AASB S2, closely mirroring the ISSB standards with Australian-specific modifications. The phased mandate applies to Group 1 entities (the largest reporters) from FY 2024-25, Group 2 from FY 2026-27, and Group 3 from FY 2027-28.
Australia’s implementation includes some notable features: modified liability provisions to encourage good-faith reporting in early years, a phased approach to Scope 3 emissions reporting, and alignment with existing Australian financial reporting architecture. Companies in the APAC region with Australian operations or listings should treat this as one of the most advanced implementation models to study.
Singapore
The Singapore Exchange (SGX) mandated ISSB-aligned climate reporting for all listed companies, making it one of the first major Asian financial centers to move from voluntary to mandatory ISSB adoption. The requirements are phased by industry, with priority sectors (finance, energy, materials) leading the way from FY 2025.
Singapore’s approach focuses initially on climate (S2-aligned) disclosures, with broader sustainability disclosures (S1-aligned) following on a later timeline. The Monetary Authority of Singapore (MAS) has also incorporated ISSB-aligned disclosure expectations into its supervisory framework for financial institutions.
Hong Kong
The Hong Kong Stock Exchange (HKEX) adopted HKFRS S1 and S2, aligned with ISSB standards, for Main Board issuers from FY 2025. The implementation includes a comply-or-explain transition period for certain requirements, allowing companies to build capabilities progressively. GEM Board issuers follow on a later timeline.
Hong Kong’s adoption is significant for companies with dual listings or significant operations across Greater China, as it establishes ISSB-aligned reporting as the standard for one of Asia’s most important capital markets.
Nigeria and Turkey
Nigeria was among the earliest jurisdictions to adopt ISSB standards outright, with the Financial Reporting Council mandating IFRS S1 and S2 for listed and significant public entities. Turkey followed with Turkish-language translations (TFRS S1/S2) adopted by the Public Oversight Authority, with a phased rollout for large public interest entities.
These early adoptions, while covering smaller capital markets, signal the breadth of ISSB’s global reach and provide implementation experience that larger jurisdictions are watching closely.
Brazil
Brazil’s securities regulator, the CVM (Comissao de Valores Mobiliarios), issued resolutions requiring ISSB-aligned climate disclosures for listed companies on a phased basis beginning FY 2026. As Latin America’s largest economy and capital market, Brazil’s adoption is influential across the region. The Central Bank of Brazil has also signaled alignment with ISSB for financial institution disclosures.
Voluntary and Considering: The Next Wave
Canada
The Canadian Sustainability Standards Board (CSSB) has issued exposure drafts based on ISSB standards, but a mandatory adoption timeline has not been confirmed as of early 2026. The regulatory environment remains in consultation, with debate around the pace and scope of mandating ISSB-aligned reporting. Companies listed on the TSX are increasingly adopting voluntarily, driven by investor expectations and cross-border listing requirements.
South Korea
South Korea established the Korea Sustainability Standards Board (KSSB) and developed ISSB-aligned standards. Voluntary adoption is encouraged from FY 2026 onward, with discussions ongoing about a mandatory timeline. Given the export orientation of Korean conglomerates and their exposure to ISSB-aligned jurisdictions (Australia, Singapore, the UK), voluntary adoption is rapidly becoming the practical norm for large listed companies.
Malaysia
Bursa Malaysia has mandated ISSB-aligned climate disclosures for Main Market listed companies beginning FY 2025, with the ACE Market following on a later timeline. Malaysia’s implementation reflects ASEAN’s broader movement toward ISSB adoption, coordinated through the ASEAN Capital Markets Forum.
Others Under Consideration
India continues to develop its sustainability reporting landscape. The existing Business Responsibility and Sustainability Reporting (BRSR) framework, mandated by SEBI, is under review for potential alignment with ISSB. No formal adoption timeline has been set, but India’s participation in ISSB stakeholder processes signals eventual convergence.
Saudi Arabia is working through the Saudi Organization for Chartered and Professional Accountants (SOCPA) to develop ISSB-aligned standards, consistent with the Kingdom’s Vision 2030 sustainability commitments.
South Africa has issued guidance through the JSE referencing ISSB, but a mandatory adoption date has not been set. The country’s existing strong governance culture (King Code) provides a foundation for eventual adoption.
The EU Question: ESRS vs. ISSB
The European Union chose a distinct path. Rather than adopting ISSB standards directly, the EU developed its own European Sustainability Reporting Standards (ESRS) under the Corporate Sustainability Reporting Directive (CSRD). The key differences are structural:
Double materiality vs. single materiality. ISSB standards adopt a single materiality lens — disclosures focused on information that is material to investors’ assessment of enterprise value. ESRS requires double materiality — companies must report on both how sustainability issues affect the business (financial materiality, aligning with ISSB) and how the business affects people and the environment (impact materiality, going beyond ISSB).
Scope of topics. ESRS covers a broader range of sustainability topics beyond climate, including biodiversity, water, circular economy, workforce conditions, affected communities, and business conduct. ISSB currently has S1 (general) and S2 (climate), with additional topical standards in development.
Mandatory vs. baseline. ESRS is a mandatory reporting standard with legal force in the EU. ISSB is designed as a global baseline that jurisdictions can adopt, adapt, or build upon.
Interoperability: The EFRAG-ISSB Mapping
Recognizing that thousands of companies will need to report under both ESRS and ISSB (or ISSB-aligned local standards), EFRAG and the ISSB have published interoperability mapping guidance. This mapping identifies:
- Common requirements — where ESRS and ISSB require materially equivalent disclosures, allowing a single data collection process to serve both
- ESRS incremental requirements — where ESRS goes beyond ISSB (primarily impact materiality disclosures and non-climate environmental topics)
- ISSB incremental requirements — where ISSB requires specific disclosures not explicitly covered by ESRS (limited cases, mainly around industry-based metrics inherited from SASB)
For multinational companies, the practical implication is that an ESRS-compliant report substantially satisfies ISSB requirements on financial materiality topics — but not vice versa. Companies starting from ISSB may need to layer on additional disclosures to satisfy ESRS. Companies starting from ESRS can typically extract an ISSB-aligned subset.
Implications for Multinationals
For companies operating across multiple jurisdictions, the fragmented adoption landscape creates several strategic challenges.
1. Mapping Your Jurisdictional Exposure
The first step is understanding which ISSB-aligned mandates apply to your specific entities. A company headquartered in Japan with listings in Hong Kong, operations in Australia, and significant EU revenue may face:
- SSBJ (Japan, FY 2027 onward)
- HKFRS S1/S2 (Hong Kong listing, FY 2025 onward)
- AASB S1/S2 (Australia operations, FY 2024-25 onward)
- CSRD/ESRS (EU revenue thresholds, Wave 4 from FY 2028)
Each jurisdiction has its own scope, timing, and modifications. Mapping this exposure at the entity level is the foundation of any compliance strategy.
2. Designing a Collect-Once, Report-Many Architecture
The most expensive mistake companies make is building separate reporting processes for each framework. The standards share substantial common ground: climate-related disclosures (TCFD-aligned), governance and risk management processes, metrics and targets, and transition plans. A well-designed data architecture collects granular sustainability data once and maps it to multiple output formats.
This requires:
- A unified data model that captures the superset of requirements across all applicable frameworks
- Automated mapping rules that generate framework-specific outputs from the common dataset
- A governance layer that manages materiality determinations, as different frameworks define materiality differently
3. Managing the Materiality Gap
The most significant conceptual difference across frameworks is materiality. ISSB uses single (financial) materiality. ESRS uses double materiality. SSBJ aligns with ISSB’s single materiality.
For companies subject to both ESRS and ISSB-aligned standards, this means conducting a double materiality assessment (as required by ESRS) and then identifying the subset of disclosures that satisfy ISSB’s financial materiality threshold. The reverse approach — starting with ISSB and trying to add ESRS — is less efficient because ESRS’s impact materiality dimension requires a fundamentally different analytical process.
4. Preparing for Convergence and Divergence
The standards landscape is still evolving. The ISSB has signaled work on additional topical standards beyond climate. National jurisdictions continue to refine their adoption approaches. The EU is considering Omnibus simplifications. Companies should build flexible reporting systems that can accommodate new requirements without structural overhauls.
Key Differences in National Implementation Approaches
Even among jurisdictions adopting ISSB, the implementation approaches vary significantly.
| Implementation Feature | Varies By | Examples |
|---|---|---|
| Scope of entities | Market cap, revenue, employee thresholds | Japan: market cap tiers; Australia: entity size groups; UK: listed vs. all large companies |
| Phase-in timeline | Jurisdiction | Australia started FY 2024-25; Japan starts FY 2027; Brazil starts FY 2026 |
| Local modifications | Regulatory context | Australia: modified liability provisions; Singapore: phased by industry sector |
| Scope 3 treatment | Readiness concerns | Several jurisdictions provide transition relief for Scope 3 emissions reporting |
| Assurance requirements | Maturity of assurance market | Some jurisdictions mandate assurance from day one; others phase it in |
| Relationship to existing frameworks | Local reporting history | Japan: SSBJ builds on existing TCFD practice; New Zealand: extends existing climate disclosure regime |
How Companies Should Prepare
Step 1: Conduct a Jurisdictional Mapping Exercise
Identify every jurisdiction where your company has listed entities, significant operations, or material revenue. For each, determine whether an ISSB-aligned mandate applies, what the scope and timing are, and what local modifications exist.
Step 2: Assess Your Current State
Evaluate your existing sustainability reporting against IFRS S1 and S2 requirements. Most companies already reporting under TCFD, GRI, or CDP have a substantial head start. The gap analysis should identify:
- Missing data points (especially Scope 3 emissions, scenario analysis, transition plans)
- Governance gaps (board-level oversight of sustainability risks)
- Process gaps (data collection, internal controls, audit trail)
Step 3: Build or Upgrade Your Data Infrastructure
Multi-framework reporting demands a data platform that can handle granular sustainability data, apply different materiality filters, and generate framework-specific outputs. Spreadsheet-based processes break down under multi-jurisdictional compliance.
Step 4: Align Materiality Processes
If you operate in both ISSB and ESRS jurisdictions, design your materiality assessment to satisfy the most demanding standard first (ESRS double materiality), then extract the ISSB-relevant subset. This avoids running parallel assessment processes.
Step 5: Engage Assurance Early
As ISSB-aligned jurisdictions increasingly require limited or reasonable assurance on sustainability disclosures, your reporting processes must be audit-ready from the start. Engaging assurance providers early — before the first mandatory reporting cycle — allows time to address process and control gaps.
The Technology Imperative
The complexity of multi-framework, multi-jurisdiction sustainability reporting makes AI-powered platforms essential rather than optional. The volume of datapoints (ESRS alone contains over 1,100 disclosure requirements), the mapping logic across frameworks, and the need for consistent, auditable data flows exceed what manual processes can reliably deliver.
Key capabilities to look for in a reporting platform:
- Multi-framework mapping — automated classification of your data against ISSB, ESRS, SSBJ, GRI, and other frameworks simultaneously
- Jurisdictional configuration — ability to define which standards apply to which entities, with appropriate scope and timing
- Materiality management — support for both single and double materiality assessments, with the ability to generate framework-specific materiality matrices
- Gap analysis — automated identification of missing datapoints against each applicable standard
- Assurance support — full audit trail from source data through to published disclosures
Socious Report is designed for exactly this challenge. As an AI-powered sustainability reporting platform, it supports IFRS S1/S2, ESRS, SSBJ, GRI, and other major frameworks natively. Companies can collect data once, define their jurisdictional exposure, and generate framework-specific reports from a single system — with automated gap analysis, materiality management, and assurance-ready documentation.
Looking Ahead
The direction is clear: ISSB-aligned sustainability reporting is becoming a global norm, not a regional experiment. By late 2026, mandatory ISSB implementation will cover major capital markets across Europe, Asia-Pacific, the Middle East, Africa, and Latin America. The US remains an outlier, but even there, investor-driven voluntary adoption is growing.
For multinational companies, the question is no longer whether to adopt ISSB-aligned reporting, but how to do it efficiently across all the jurisdictions where it applies — while simultaneously meeting ESRS requirements where the EU mandates apply.
Companies that invest now in unified data infrastructure and multi-framework reporting capabilities will be positioned not just for compliance, but for the kind of transparent, decision-useful sustainability disclosure that investors and regulators increasingly demand.
Need to navigate ISSB adoption across multiple jurisdictions? Book a demo of Socious Report to see how AI-powered multi-framework reporting simplifies compliance from IFRS S1/S2 to ESRS and SSBJ.
This article reflects ISSB adoption status as of March 2026. Regulatory timelines and scope details are subject to change as jurisdictions finalize their implementation approaches. Companies should consult legal counsel for jurisdiction-specific obligations. Sources: IFRS Foundation — ISSB Standards, IFRS Foundation — Jurisdictional Adoption Tracker, EFRAG-ISSB Interoperability Guidance, AASB Sustainability Standards, SSBJ Standards, SGX Sustainability Reporting, HKEX Climate Disclosure, FCA UK SRS