Sovereign Cloud Comparison: AWS EU Sovereign vs Azure Confidential Cloud vs Google Assured

Hook: Why enterprise architects can’t treat sovereignty as a checkbox

Choosing a sovereign cloud in Europe is no longer about simple data residency. You face competing priorities: predictable capacity and cost, airtight legal protections against extraterritorial access, developer-friendly APIs that plug into CI/CD, and demonstrable compliance with DORA, NIS2 and evolving EU rules. In 2026 the market has shifted—vendors now offer regionally isolated platforms, confidential computing primitives, and new contractual assurances. But the differences are consequential. This head-to-head sovereign cloud comparison will give enterprise architects the feature, compliance, legal and cost framework required to choose between AWS European Sovereign Cloud, Azure Confidential and Google Assured.

Executive summary (TL;DR)

• AWS European Sovereign Cloud: Strong focus on physical/logical separation and independent European control domains. Best when legal guarantees and separation are primary drivers.
• Azure Confidential: Leading confidential-computing integrations and enterprise tooling; attractive when you need seamless Azure ecosystem integration plus TEEs and customer-managed keys.
• Google Assured: Emphasizes automation for compliance, granular policy controls and developer ergonomics; best for data-centric apps that need flexible assurance controls and platform-native data services.
• All three now address EU sovereignty needs but differ on how they combine personnel controls, contractual protections, cryptographic key custody and cost models. Use the checklist and PoC plan in this guide to validate vendor claims against your legal and performance SLAs.

2025–2026 context: new rules, new vendor guarantees

Late 2025 and early 2026 accelerated two trends that matter to architects:

• Regulatory pressure (DORA for financial services, NIS2, and evolving EU data governance guidance) pushed cloud providers to deliver contractual and technical sovereignty controls beyond simple residency.
• Confidential computing, TEEs, and customer-controlled HSMs matured from prototypes to production-ready services, making cryptographic isolation a key differentiator for sovereign clouds. See notes on confidential and edge analytics for workload patterns that benefit from in-use protections.

Data residency alone is not enough—regulators and auditors now expect demonstrable governance, personnel controls, and cryptographic separation.

Head-to-head: Feature and control comparison

1) Isolation model: physical, logical, and legal separation

Why it matters: Isolation determines whether your data and metadata can be accessed by non-EU entities or vendor global teams.

• AWS European Sovereign Cloud: Built as an independent AWS cloud inside the EU with physical and logical separation, dedicated control planes and an independent European control plane domain. AWS emphasizes localized operational staff and legal commitments limiting cross-border administrative access.
• Azure Confidential: Typically leverages dedicated regions and isolation options with powerful role-based controls and Azure Resource Manager policies; isolation is often combined with confidential computing to reduce attack surface rather than providing completely separate global control planes.
• Google Assured: Focuses on configurable assurance per project or workload—data residency plus granular assurance controls. Google combines regional controls with strong automation to lock down access and auditing for designated workloads.

2) Personnel access and EU-only administrative controls

Key evaluation points: Who can access metadata, keys and logs? Are administrators EU-based and subject to EU law?

• AWS: Public messaging in early 2026 highlights EU-based administrative controls and restricted personnel access for the sovereign cloud. Expect detailed SOC/SR controls and contractual clauses that limit non‑EU employee access.
• Azure: Offers Customer Lockbox, Privileged Identity Management and options to enforce EU-only admin via contractual commitments for specific sovereign deployments—validate exact staffing commitments in your contract.
• Google: Uses granular IAM and access transparency plus configurable assurance levels. Google historically provides strong audit logs and tools to demonstrate who accessed data, but you must verify EU-personnel coverage for your specific Assured configuration.

3) Legal & contractual protections (extraterritorial access, warrants, subpoenas)

What to negotiate: Clear clauses that address cross-border government access, notification, and contestability; explicit limits on where data can be accessed for support and admin tasks.

• AWS: The European Sovereign Cloud marketing emphasizes legal protections and sovereign assurances; AWS aims to provide contractual commitments limiting non‑EU access. Request explicit language on government requests and notification timelines.
• Azure: Historically strong at contract-driven controls—ask for explicit EU‑only support commitments, data handling clauses and legal remedies. Microsoft has been willing to add tailored language for large public-sector customers.
• Google: Google Assured includes enforceable controls, but legal terms can vary. Insist on explicit handling of law-enforcement requests and on the vendor’s obligations to challenge requests where possible. Bring your legal and migration teams early (see our platform migration playbook at platform migration guidance).

4) Encryption and key management

Controls to demand: Customer-managed keys (CMEK), HSM-backed keys, BYOK/HYOK options, and support for external key custody.

• AWS: Supports AWS KMS in regional boundaries, dedicated HSMs and external key partners. For sovereign clouds, verify whether keys can be kept in EU-only HSMs and whether AWS (or any non-EU personnel) can access key material.
• Azure: Strong enterprise feature set—Azure Key Vault Managed HSM, customer-managed keys, and Azure Dedicated HSM. Azure Confidential integrates with these for workflow-level protections.
• Google: Cloud KMS and External Key Manager integrations are available; Google Assured adds governance controls to ensure keys and secrets follow EU residency policies. Validate whether CMEK/EKM endpoints are hosted inside the sovereign boundary. For long-term cryptographic strategy, start tracking advances in post-quantum and SDK tooling (see Quantum SDKs and developer experience).

5) Confidential computing and runtime isolation

Confidential computing reduces risk by protecting data in use. This is now a first-class requirement for many regulated workloads.

• AWS: Offers Nitro-based confidential instances and hardware-backed enclave options; check which instance families are available in the sovereign cloud region.
• Azure: Market leader in confidential computing integrations (e.g., Confidential VMs, SGX and SEV support) and has deep integration with Azure Active Directory, Key Vault and developer tooling—an advantage for CI/CD pipelines.
• Google: Supports confidential VMs and confidential GKE nodes; Google’s tooling emphasizes developer ergonomics for confidential workloads and automated policy enforcement under Assured configurations.

6) Compliance, certifications and audit transparency

Essential certifications and directives to check: GDPR, ISO 27001, SOC 1/2/3, NIS2, and DORA applicability for financial firms.

• AWS: Sovereign cloud variants typically bring region-specific attestations and independent audits. Request SOC reports for the sovereign control plane and evidence of NIS2/DORA alignment.
• Azure: Broad certification portfolio; Azure Confidential deployments generally include attestation artifacts suitable for audits and regulator reviews.
• Google: Assured features aim to automate compliance evidence collection; confirm that Google provides the specific attestations and audit artifacts your regulator expects. Use a compliance matrix and diagram pack when you ask vendors for evidence to speed auditor review.

Pricing and cost predictability: how sovereign clouds change the model

All three vendors typically charge a premium for sovereign or dedicated deployments. The premium shows up in three places: infrastructure (region surcharge), operational support (EU-only staff, legal commitments), and additional services (HSM, confidential computing, higher SLAs).

Cost drivers to model

• Storage capacity and tiering (hot vs cold).
• Network egress and inter-region replication costs.
• HSM/CMEK/EKM charges and per‑KMS request costs.
• Confidential computing instance premiums and licensing.
• Support and auditing (custom contract/legal review fees).

Actionable tip: build a 3-year TCO with scenario runs (baseline, peak, disaster replication) and include negotiation levers: committed use discounts (CUDs), reserved instances, and negotiated egress caps. Don’t forget DORA-specific uptime and incident response requirements—these can drive premium support costs. If your architecture needs low-latency, region-to-region replication, review local networking trends and venue connectivity options (including local-first 5G) as part of your network cost model—see local-first 5G notes.

Compliance matrix: practical controls to require

Below is a condensed compliance matrix you can use during vendor evaluation. Ask vendors to provide evidence or attestations for each item for their sovereign offering.

• Data residency: Data-at-rest and metadata stored exclusively in EU data centers? (Yes/No + evidence)
• Administrative access: EU-only admin staffing and background checks? (Yes/No + staff roster policy)
• Legal protections: Contract clause on extraterritorial data access and obligation to challenge non-EU requests
• Key custody: CMEK/EKM/HYOK in EU-controlled HSMs
• Confidential compute: Availability of TEEs and attestation for workloads
• Auditability: Access transparency, searchable audit logs, and timestamped attestation artifacts
• Certifications: ISO, SOC reports, EU-specific attestation for NIS2/DORA concerns
• SLAs & remedies: Uptime commitments, incident response, and contractual remedies for breaches

Vendor negotiation checklist (questions to ask in RFP/POC)

1. Can you provide the sovereignty-specific contract addendum with EU-only administrative access and detailed notification procedures for legal requests?
2. Where are cryptographic keys (KMS/HSM) physically hosted and who has access to key material? Can we use an external HSM that we control? (Document your EKM options and latency requirements.)
3. Which confidential compute instance types are available in the sovereign region and what are the attestation flows for CI/CD?
4. Provide sample SOC/ISO reports and an evidence pack for the sovereign control plane and region.
5. Show costs for 3-year committed usage and list red-lines for egress, replication and HSM fees.
6. Supply a runbook for incident response aligned to DORA reporting timelines.

Proof-of-concept (PoC) plan for storage-heavy sovereign workloads

Run the same PoC across all three vendors to compare performance, controls and cost:

1. Deploy a realistic dataset (e.g., 100TB with mixed object and block storage) and configure lifecycle rules to reflect production policies.
2. Enable CMEK with a cluster-hosted HSM in-region (or EKM integration) and measure latency for key operations.
3. Spin up confidential compute nodes and run a data-processing pipeline to measure throughput and encryption/attestation overhead.
4. Simulate support escalation and request a staff-access audit to validate EU-only admin claims.
5. Collect billing across 30 days of steady-state and burst traffic and extrapolate a 12‑month cost model under three scenarios. Include event and stream load patterns (see event stream benchmarks).

Practical cost-saving strategies for sovereign deployments

• Localize only what you must. Not all datasets require sovereign handling—split datasets by sensitivity and apply local residency only where needed.
• Use tiering aggressively. Cold object tiers cut storage costs, and lifecycle automation can save significant money at scale. Edge architecture patterns in privacy-first edge designs can help identify what to localize.
• Negotiate committed usage discounts and egress caps early in contract talks—sovereign wings often have more room to negotiate due to deployment complexity.
• Consolidate KMS/HSM usage. Centralize keys for multiple projects where acceptable, to reduce per-key HSM fees.
• Benchmark confidential compute performance vs cost and evaluate secure enclaves only for workloads that benefit from in-use protection.

Operational integration: DevOps, CI/CD, and hybrid architectures

Developer ergonomics are often the hidden cost of sovereignty. Your team must be able to deploy, monitor and iterate without manual gating for every operation.

• Ensure the vendor supports the same APIs and IaC (Terraform, Pulumi, ARM/Bicep, Google Deployment Manager) in the sovereign region. Use CI/CD and IaC guidance like the patterns in CI/CD playbooks.
• Verify that secrets management integrates with your CI/CD system and that ephemeral build credentials respect EU-only KMS policies.
• Design a hybrid network topology (Direct Interconnect / ExpressRoute / AWS Direct Connect equivalents) that keeps traffic within the EU for replication and backup. Local connectivity and venue networking guidance (including trends in local-first 5G) can influence your runbook for replication.

Hypothetical case study: EU bank migrating 5 PB of client data

Scenario: A pan‑EU bank must move 5 PB of customer records into a sovereign cloud supporting DORA and GDPR. Key decisions:

1. Data classification—40% must remain in EU-only, 60% can be in regional public cloud for analytics.
2. Encryption—customer-managed HSMs in-region; vendor must sign contractual commitment restricting non-EU access.
3. Performance—transactional systems run on confidential VMs with sub‑millisecond KMS latency requirement.

Outcome summary:

• If the bank prioritizes legal separation and a separate control plane, AWS European Sovereign Cloud is attractive for its independent domain and contractual positioning.
• If the bank prioritizes confidential computing with tight CI/CD and Active Directory integrations, Azure Confidential’s developer experience and managed HSMs are compelling.
• If the bank requires automated compliance evidence, granular per-workload assurance and platform-native analytics, Google Assured balances controls with developer ergonomics.

Future predictions: what to expect in 2026–2028

• Increased standardization: expect stronger industry templates for sovereign contracts and playbooks for DORA/NIS2 compliance.
• Confidential computing will become default for sensitive workloads—expect narrower performance gaps and lower premiums for TEEs.
• Multi-vendor sovereign architectures will grow: enterprises will increasingly use more than one sovereign provider to reduce vendor risk. Also track advances in quantum SDKs and how they may affect key management roadmaps.

Actionable takeaways for enterprise architects

• Map data and workloads to risk categories and apply sovereign controls only where necessary to reduce cost and complexity. See edge and privacy patterns in Edge for Microbrands.
• Run an identical PoC across vendors that includes CMEK, confidential compute and legal/operational review—don’t rely on marketing claims.
• Negotiate EU-only administrative clauses, explicit handling of law-enforcement requests, and a runbook for DORA timelines as part of your SLA.
• Include auditors and legal counsel early in RFPs to validate vendor evidence packs for NIS2 and DORA. Use embedded diagrams and compliance matrices to speed reviews (example tooling at embedded diagram experiences).
• Plan for multi-cloud failover of sensitive workloads to reduce sovereignty single-point-of-failure risk.

Closing: choosing the right sovereign partner

There is no one-size-fits-all answer. AWS European Sovereign Cloud emphasizes independent control planes and EU personnel commitments; Azure Confidential leads on confidential computing integration and enterprise tooling; and Google Assured delivers automation and per-workload assurance controls that favor developer agility. Use the compliance matrix, PoC plan and negotiation checklist above as your evaluation backbone—then align the vendor’s strengths with your organization’s legal, performance and cost priorities.

Call to action

Ready to run a three-way PoC or to map your data-classification to a sovereign cloud strategy? Contact our architecture team at megastorage.cloud for a free 60‑minute review and a customized sovereign cloud checklist you can use in RFPs and contract negotiations.

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