How to find the right Assurance provider for ISO 27001 and SOC 2

Choosing the right assurance provider for ISO 27001 certification and SOC 2 attestation can feel overwhelming. Many Compliance Officers and CISOs say they're uncertain where to start, especially when their organisation needs to meet both standards simultaneously.

This guide, gives you an overview of what to look for in an ISO 27001 and SOC 2 assurance provider, how to evaluate your options, and why getting it right the first time can save you time, budget, and headaches down the line.

Before diving into provider selection, it's worth grounding ourselves in why these frameworks are essential.

ISO 27001 is an internationally recognised standard for Information Security Management Systems (ISMS). It demonstrates to clients, regulators, and stakeholders that you've implemented a comprehensive, risk-based approach to protecting sensitive information. The certification process involves a formal two-stage external audit conducted by an accredited certification body, and once achieved, it's valid for three years with annual surveillance audits.

SOC 2, on the other hand, is an attestation framework developed by the American Institute of CPAs (AICPA) based on Trust Services Criteria, covering security, availability, processing integrity, confidentiality, and privacy. While it originated in North America, many European SaaS and tech companies now pursue SOC 2 because their clients (particularly those in the US market) demand it. Unlike ISO 27001, SOC 2 results in an attestation report (Type I or Type II) rather than a certificate, and it must be conducted by a licensed CPA firm.

Both frameworks share a common goal: assuring your customers that you take data security seriously. Remarkably, there's around 40% overlap in the controls required by ISO 27001 and SOC 2, which is why many organisations are now pursuing both under a single integrated audit process—saving time, cost, and audit fatigue.

When evaluating potential ISO 27001 and SOC 2 audit firms, keep these key criteria front of mind:

Accreditation and credentials

For ISO 27001, ensure the certification body is accredited by a reputable national accreditation body (such as UKAS in the UK, ANAB in the US, or RvA in the Netherlands). This guarantees the certification will be recognised globally and meet the highest audit standards.

For SOC 2, the firm must be a licensed CPA practice accredited by the AICPA. Only accredited CPA firms can issue valid SOC 2 reports under SSAE 18 / AT-C 205 attestation standards.

Experience across both frameworks

Look for providers who specialise in both ISO 27001 and SOC 2, ideally offering combined or integrated audit services. Firms experienced in dual compliance understand the overlapping controls and can streamline the assessment process, reducing duplication and accelerating your timeline to compliance.

Audit quality and thoroughness

Beware of providers promising unrealistically fast certification or "guaranteed pass" outcomes. High-quality auditors will conduct thorough gap assessments, challenge your controls, and provide actionable recommendations. Ask prospective firms for case studies, sample timelines, and references from clients in similar industries.

Advisory and readiness support

The best assurance providers don't just audit but guide you through the entire process. This is especially valuable if your organisation is pursuing compliance for the first time or has limited internal resources.

Sector and regional expertise

Consider whether the provider has experience in your industry (SaaS, fintech, healthcare, etc.) and geography. For example, European organisations may benefit from providers familiar with GDPR, NIS2, and local regulatory nuances, in addition to ISO 27001 and SOC 2 requirements.

How to choose: A practical checklist

Here's a simple framework to guide your selection:

1. Define your scope and objectives. Are you seeking ISO 27001, SOC 2, or both? What's your target timeline? What's your current security maturity?
2. Verify accreditation. Check that ISO 27001 providers are accredited by UKAS or equivalent, and SOC 2 providers are AICPA-accredited CPA firms.
3. Evaluate their approach. Do they offer readiness support? Will they assign a dedicated team? How do they handle evidence collection and non-conformity remediation?
4. Check references and case studies. Speak to past clients in your industry and review success stories.
5. Assess cultural fit. Compliance is a partnership, not a transaction. Choose a provider whose communication style, values, and service philosophy align with your organisation.

The benefits of an integrated approach

Pursuing ISO 27001 and SOC 2 together under a single assurance provider offers several strategic advantages:

• Reduced audit fatigue: One integrated assessment instead of two separate processes.
• Cost savings: Overlapping controls mean less duplication of effort and lower overall fees.
• Faster time to compliance: Streamlined evidence collection and assessment phases.
• Stronger market positioning: Holding both certifications enhances credibility with European and North American clients alike.
• Improved governance: A unified ISMS and control framework simplifies ongoing compliance and risk management.

If your organisation operates in a global SaaS or tech environment, the combination of ISO 27001 and SOC 2 is increasingly becoming table stakes. Clients now expect robust security assurances, and having both standards demonstrates a mature, comprehensive approach to information security.

Final thoughts

Take your time to evaluate providers carefully, ask the tough questions, and choose a partner who will guide you beyond the audit to embed security and compliance into the DNA of your organisation. Whether you're just starting your compliance journey or refining an existing programme, the right assurance provider will help you turn compliance from a burden into a business advantage.