ESG Reporting Timeline: Key Dates and Deadlines for Australian Businesses (2025–2028)

Australia’s mandatory sustainability reporting framework has a clear, phased timeline designed to give organisations progressive implementation periods. Understanding the exact dates for your reporting group is essential for planning compliance activities. This guide provides a comprehensive timeline of all key AASB S1 and AASB S2 deadlines through 2028.

For broader ESG strategy context, see our complete ESG guide for Australian businesses.

High-Level Timeline Overview

Group 1: Detailed Timeline (Large Entities and ASX-Listed Companies)

Phase 0: Preparation (Now – December 2024)

• Now: Confirm Group 1 status; undertake materiality assessment; establish governance structures
• Q3 2024: Begin data collection infrastructure development; engage sustainability advisors and external assurance providers; draft disclosure strategy
• Q4 2024: Finalise data systems and controls; conduct pilot data collection; engage assurance provider and brief them on reporting intention

Phase 1: FY2025–26 Reporting Period (1 January 2025 – 31 December 2025 or aligned to your FY)

• 1 January 2025: First reporting period begins for all Group 1 entities
• Throughout 2025: Collect sustainability data in accordance with planned disclosures; manage ongoing governance processes; track progress against any targets
• 31 December 2025 (sample balance date): End of first reporting period (adjust to your actual balance date)

Phase 2: Reporting and Publication (January – March 2026)

• January 2026: Consolidate sustainability data; prepare sustainability report draft; brief internal stakeholders
• February 2026: External assurance commences; finalise disclosures based on auditor feedback
• 31 March 2026 (sample deadline): First sustainability report must be lodged/published (90 days after balance date for 31 Dec balance)

Phase 3: Lodgement and Transparency (April 2026 onwards)

• April 2026: Report publicly available; investor and stakeholder engagement on disclosures
• 2026 onwards: Begin planning for next year’s reporting cycle; refine governance and data collection based on first year experience

Group 2: Detailed Timeline (Medium-Sized Entities)

Phase 0: Preparation (Now – December 2025)

• Now – Q2 2025: Confirm Group 2 status; conduct materiality assessment; establish governance structures and steering committee
• Q3 2025: Design data collection systems; identify and brief potential assurance providers; develop disclosure framework and reporting structure
• Q4 2025: Finalise systems and controls; conduct pilot/test data collection; select and formally engage external assurance provider

Phase 1: FY2026–27 Reporting Period (1 January 2026 – 31 December 2026 or aligned to your FY)

• 1 January 2026: First reporting period begins for all Group 2 entities
• Throughout 2026: Execute full-scale data collection; implement governance processes; track any declared targets; address data quality issues identified in pilot
• 31 December 2026: End of first reporting period (adjust to your actual balance date)

Phase 2: Reporting and Publication (January – March 2027)

• January 2027: Data consolidation and report drafting; internal review and approval
• February 2027: External assurance process; final refinements to disclosure
• 31 March 2027 (sample deadline): First sustainability report must be lodged/published

Group 3: Detailed Timeline (Smaller Reporting Entities)

Phase 0: Preparation (Now – December 2026)

• Now – Q2 2026: Confirm Group 3 status; conduct initial scoping and materiality assessment; establish governance and stakeholder engagement plan
• Q3 2026: Identify and brief external assurance providers; develop reporting and disclosure strategy; plan data collection approach
• Q4 2026: Implement data collection systems; conduct initial data trials; engage external assurance provider; confirm disclosure scope

Phase 1: FY2027–28 Reporting Period (1 January 2027 – 31 December 2027 or aligned to your FY)

• 1 January 2027: First reporting period begins for all Group 3 entities
• Throughout 2027: Execute full data collection cycle; implement governance processes; manage any transitions or system changes based on Group 1 and Group 2 experience published to date
• 31 December 2027: End of first reporting period (adjust to your actual balance date)

Phase 2: Reporting and Publication (January – March 2028)

• January 2028: Data consolidation; report drafting; internal review
• February 2028: External assurance; final revisions
• 31 March 2028 (sample deadline): First sustainability report must be lodged/published

Specific Reporting Deadlines by Financial Year End

The lodgement deadline is 90 days after the end of your financial year. Here are examples for common financial year end dates:

Key Implementation Milestones by Year

2024 (Immediate Actions)

• Confirm reporting group assignment
• Begin governance structures and board/management alignment
• Scope materiality assessment
• Plan data systems and infrastructure investment
• Identify external advisors and assurance providers

2025 (Group 1 Execution Year)

• January: Group 1 first reporting period begins
• Throughout: Group 1 collects first year of sustainability data; Group 2 undertakes detailed preparation; Group 3 begins planning
• Q4: Group 1 report drafting and assurance; Group 2 systems finalisation

2026 (Group 1 Reporting; Group 2 Execution Begins)

• Q1: Group 1 first reports published (31 March deadline for 31 Dec year-ends)
• January: Group 2 first reporting period begins
• Throughout: Group 2 collects first year data; Group 3 finalises systems and preparation
• Q4: Group 2 report drafting and assurance

2027 (Group 2 Reporting; Group 3 Execution Begins)

• Q1: Group 2 first reports published (31 March deadline for 31 Dec year-ends)
• January: Group 3 first reporting period begins
• Throughout: Group 3 collects first year data; experience from Group 1 and 2 reports informs market practice
• Q4: Group 3 report drafting and assurance

2028 (Group 3 Reporting; Ongoing Cycles)

• Q1: Group 3 first reports published (31 March deadline for 31 Dec year-ends)
• Throughout: All groups in second/subsequent reporting cycles; continuous refinement of data processes and governance based on market practice and emerging guidance

Planning for Your Implementation

For Group 1 Entities: Time Is Critical

Group 1 organisations are in the execution phase now (mid-2024). If you haven’t already begun preparation, immediate action is required to meet 2026 reporting deadlines. Focus on governance establishment, materiality assessment completion, and data systems implementation in the remaining months of 2024.

For Group 2 Entities: Planning Phase Now

Group 2 organisations have approximately 12 months to complete preparation before data collection begins (January 2026). Use this time to learn from Group 1 early disclosures (expected Q1 2026) and refine your approach based on market practice and regulatory guidance.

For Group 3 Entities: Strategic Preparation

Group 3 organisations have the most time (24+ months from now) to prepare. However, this is an opportunity to develop sophisticated, efficient systems rather than rushing. Begin materiality assessment and governance scoping now to be well-positioned when reporting begins.

Beyond 2028: Ongoing Reporting Cycles

After first reporting, all groups will report annually. The 90-day lodgement deadline applies to all subsequent reports. Organisations should embed sustainability reporting into annual financial reporting processes, with data collection and governance occurring continuously throughout each financial year.

Frequently Asked Questions

If our financial year doesn’t end on 31 December, what is our deadline?

Your deadline is 90 days after your balance date. For example, if your financial year ends on 30 June, your Group 1 first report is due 30 September (for reporting on FY2025–26 ending 30 June 2026).

What if we can’t meet the deadline?

ASIC can provide transitional relief in exceptional circumstances, but you should not assume this will be granted. Plan to meet the deadline. If you anticipate difficulty, seek guidance from ASIC early.

Once we report the first year, do we have the same 90-day deadline every year?

Yes. The 90-day lodgement deadline applies to all subsequent annual reports once the initial report has been published.

Should we begin data collection before the official reporting period start date?

Yes. Organisations should conduct pilot data collection during the year before their first reporting period to identify system gaps, data quality issues, and governance refinements needed.

Can we change our reporting year to align with a different calendar period?

Financial year changes may be possible but require regulatory approval and can complicate comparability. Unless there is a compelling business reason, align sustainability reporting with your existing financial reporting year.

Moving Forward with Timeline Planning

Successful AASB S1 and S2 compliance requires structured, phased planning aligned with your reporting group’s timeline. Group 1 entities must act immediately; Group 2 should intensify planning in 2024; Group 3 has more time but should use it wisely to build sophisticated systems. All organisations benefit from early governance establishment, materiality assessment, and data systems development.

Ready to develop a detailed compliance timeline for your organisation? Book a Free ESG Strategy Session to map your specific reporting obligations and compliance roadmap.