How to Prepare for Your First CSRD Audit or Review

Introduction

Your first CSRD audit or review can feel daunting — but with clear preparation, it’s simply the next logical step in your reporting journey. From 2024 onward, companies reporting under the Corporate Sustainability Reporting Directive (CSRD) must ensure their sustainability disclosures are subject to limited assurance, confirming data accuracy and process reliability.

For small and growing businesses (SMEs) and suppliers adopting the VSME Standard, external review may not be legally required but is increasingly expected by banks, investors, and corporate clients. Preparing early will help build trust and reduce future assurance costs.

Before diving in, it’s helpful to revisit your company’s reporting structure. If you haven’t already, see our guide on annual CSRD reporting calendars for an overview of when to gather data for audit readiness.

1. Understand the Type of Assurance You’ll Undergo

Under the CSRD, the first level of verification is limited assurance, focused on ensuring your sustainability report is free from material misstatements and aligns with ESRS (European Sustainability Reporting Standards). Over time, the EU may progress to reasonable assurance, similar to a financial audit.

For SMEs reporting voluntarily under the VSME framework, assurance remains optional. However, demonstrating that your data follows VSME’s principles of relevance, comparability, and verifiability strengthens stakeholder confidence and can improve access to finance.

2. Gather and Organise Evidence Early

Auditors will check the traceability of your sustainability data — where each figure comes from and how it was calculated. To prepare:

• Keep source documentation (invoices, meter readings, payroll files, supplier statements).
• Maintain a data log showing when and by whom each figure was entered or updated.
• Store files in a shared location with clear version control.
• Document your data collection methods (e.g. how you estimate Scope 3 emissions).

Creating a clear audit trail is one of the most effective ways to demonstrate compliance. Many SMEs find it useful to align this with their existing data workflow — see our article on integrating CSRD data collection into existing workflows.

3. Review Consistency Between Financial and Sustainability Data

Both the CSRD Directive and VSME Standard stress the need for coherence between financial and non-financial data. This means your reported sustainability impacts should logically align with your financial results — for instance, energy spending should correspond to reported energy use, or employee figures should match HR payroll records.

Tip: Have your finance and sustainability teams review the same datasets together before submission. This proactive step reduces auditor queries and signals strong internal control.

4. Conduct an Internal Pre-Audit

Before involving external auditors, perform a light internal review. Use your reporting framework as a checklist:

• Have you reported on all relevant ESRS topics (e.g., energy, water, workforce)?
• Are data sources consistent and documented?
• Have assumptions or estimations been clearly stated?
• Are your sustainability policies and practices (VSME B2) up to date?

An internal pre-audit helps spot data gaps or unclear disclosures early, saving time and cost during the external review.

5. Communicate and Train Your Team

Audits aren’t just about numbers — they test processes and awareness. Make sure your team understands:

• The purpose of the CSRD review.
• How data is collected and validated in their department.
• What documentation may be requested by auditors.

A brief training or Q&A session can go a long way in ensuring everyone feels prepared and confident.

6. Engage with Auditors Proactively

Once your audit date is set, contact your auditor early to clarify expectations:

• What level of documentation is required?
• How will they access your systems or reports?
• Which areas will they focus on most?

Being proactive helps manage timelines and prevents last-minute stress. Remember: an audit is a collaborative process, not a compliance trap.

Frequently Asked Questions

What is “limited assurance” under CSRD?

Limited assurance means the auditor reviews processes, sampling, and data accuracy but does not test every item in full detail. It’s designed to provide moderate confidence that your report is reliable — the first step before future “reasonable assurance.”

Do small and growing businesses (SMEs) need an external audit?

Not necessarily. Under the VSME Standard, assurance is voluntary, though recommended if you want to improve credibility or meet large clients’ supply chain expectations. See our explainer on VSME Basic vs Comprehensive Module for how assurance fits in.

What documents should I prepare for the audit?

Keep records for key CSRD topics: energy invoices, HR data, waste management receipts, and any environmental permits. Each data point should have clear evidence and a contact person responsible for its accuracy.

How can I make the audit easier next year?

Automate your data collection and version control processes. Tools that track source data and updates automatically reduce the time spent cross-checking figures. For a setup guide, read how to build a CSRD reporting system from scratch.

Key Terms

• CSRD – Corporate Sustainability Reporting Directive (EU 2022/2464) introducing mandatory sustainability reporting for large and listed companies.
• VSME – Voluntary standard for SMEs developed by EFRAG for proportionate reporting.
• ESRS – European Sustainability Reporting Standards defining required disclosure topics and structure.
• Assurance – Independent verification of sustainability data by an external reviewer.
• Limited Assurance – Moderate confidence level audit verifying data completeness and accuracy.
• Reasonable Assurance – Higher-level audit similar to financial statement reviews.

Conclusion

Preparing for your first CSRD audit or review is about readiness, not perfection. By building clear documentation, aligning financial and sustainability data, and involving your team early, you’ll turn what feels like a compliance hurdle into a valuable credibility milestone.

For continued guidance, explore our related article on annual CSRD reporting calendars to keep your audit preparation running smoothly throughout the year.