awsmigrationsovereignty

Migrating to AWS European Sovereign Cloud: A Technical Migration Checklist

vvarious

2026-01-25

12 min read

Step-by-step technical and legal checklist to migrate sensitive workloads to the AWS European Sovereign Cloud—network, KMS, logging, and compliance.

Hook: Why your next sensitive workload should not be an afterthought

If you're responsible for migrating regulated or sensitive workloads—finance, health, public sector, or critical infrastructure—you already know the pain: fragmented controls, unclear data residency guarantees, and rising legal scrutiny across the EU. The launch of the AWS European Sovereign Cloud in January 2026 creates a viable target for bringing sensitive data and services back under EU technical, contractual and operational controls. This article gives you a practitioner-focused, step-by-step migration checklist plus the architecture and legal changes required to move production workloads into the new independent EU sovereign region.

Executive summary — what matters most (inverted pyramid)

Short version for decision-makers: treat a sovereign-region migration like a combined cloud architecture, legal, and telecom project. Prioritize four things first: (1) Data classification and residency mapping, (2) Legal & contractual assurances, (3) Network and management-plane separation, and (4) In-region logging, key management and backups. The rest—CICD, DNS, and application cutover—follow clear patterns we outline below.

Context: why 2026 matters

Regulatory enforcement across the EU tightened through 2024–2025 driven by NIS2 implementation and heightened data-residency scrutiny. AWS responded by launching the AWS European Sovereign Cloud (Jan 2026) — a physically and logically isolated AWS region with sovereign assurances intended to satisfy EU requirements for data residency and separation controls. That changes migration decisions for organizations that previously wrestled with split architectures and complex contractual addenda.

High-level migration phases

Prepare & assess
Design (legal + architecture)
Build (accounts, network, IAM, KMS)
Migrate data and applications
Validate, cut over, and harden
Operate and audit

Complete technical migration checklist (step-by-step)

Phase 0 — Project setup

Form a cross-functional team: cloud engineers, network, security, legal/DPO, procurement, and local telco contacts.
Define success criteria: RTO/RPO, residency guarantees, SLA targets, acceptable third-party exposure, and cost envelope.
Create a migration runbook and emergency rollback plan mapped to each application.

Phase 1 — Prepare & inventory

Inventory every workload and dataset. Tag items by classification: restricted, confidential, internal-only, public.
Map data flows: which services, APIs, network paths, and third-party integrations touch the data.
Identify inbound/outbound transfer points (SaaS, analytics, external APIs).
Decide which workloads must remain or move to the EU sovereign region vs. those that can stay in standard regions.

Phase 2 — Legal & compliance controls

Engage legal and procurement early. Practical items:

Obtain AWS sovereign-region contractual assurances and any available Data Processing Addendum (DPA) or Sovereign Assurance Addendum. Record the scope and limitations.
Update internal policies and Data Protection Impact Assessments (DPIA) to reflect the target region and technical controls.
Define acceptable law‑enforcement and government access policies and record any AWS commitments regarding access under applicable laws.
Confirm cross-border transfer mechanisms for any residual exports (SCCs, adequacy, or new EU transfer frameworks in place as of 2026).

Phase 3 — Account architecture and separation controls

Design from the start for isolation:

Create a dedicated AWS Organization root for sovereign workloads or dedicated OU separated from global workloads.
Enforce Service Control Policies (SCPs) to prevent accidental creation of resources outside the sovereign region.
Design a multi-account model: production accounts, sandbox/test accounts (if allowed), security/logging account, and a restricted management account. Keep the management plane minimal.
Use Control Tower or Landing Zone patterns but ensure templates and guardrails are sovereign-region-aware.

Phase 4 — Network design and telecom connectivity

The network is the single most critical area to get right.

Prefer private connectivity: deploy dedicated connections (e.g., Direct Connect equivalent offered inside the sovereign region or partner interconnects) to local EU on-ramps or IXs to avoid internet egress.
Use a regional Transit Gateway / transit architecture inside the sovereign region. Do not peering-link the sovereign region to non-sovereign AWS regions unless explicitly permitted and documented.
Design VPC segmentation: use multiple VPCs for application tiers (web, app, db), and enforce security groups and NACLs. Use Network Firewall and per-VPC routing controls.
Use VPC endpoints (PrivateLink, Gateway endpoints) for S3, DynamoDB, and service APIs to keep traffic in-region and avoid public internet egress.
Restrict outbound egress with proxy / NAT solutions and egress filtering. Block direct internet access from sensitive subnets.
Evaluate multi-AZ presence within the sovereign region for high availability; DR must be in-region or within an approved EU sovereign boundary.

Phase 5 — Identity, keys, and secrets

Centralize identity: integrate the sovereign region with your EU identity provider (SAML/OIDC) but ensure tokens/sessions don’t transit outside the region unless acceptable.
Use IAM least privilege and permission boundaries; apply Attribute-Based Access Control for fine-grained policies.
Use customer-managed KMS keys created and stored in-region. If you require external key control, evaluate XKS (external key store) or CloudHSM appliances hosted in-region.
Ensure secrets management (Secrets Manager/Parameter Store) is region-specific and that retrievals do not cross sovereign boundaries.

Phase 6 — Logging, monitoring, and auditing

Centralize logs to an in-region logging account: CloudTrail, VPC Flow Logs, ALBs, and application logs — keep them in-region and write retention and access policies.
Enable AWS Config, Security Hub, and GuardDuty equivalents in-region and forward findings only within the sovereign environment unless explicit export is approved.
Integrate your SIEM or analytics platform with in-region log buckets or consider deploying SIEM replicas inside the sovereign region.
Implement automated evidence collection for compliance audits (immutable logs, snapshots of config rules).

Phase 7 — Data migration strategy

Select methods by workload type:

Databases: use AWS DMS with endpoints inside the sovereign region for full load + CDC. For very large datasets, use physical transfer appliances or seeding via local partner connectivity.
Block storage/VMs: create in-region AMIs and snapshots. Use replication tools that respect residency (do not copy snapshots to non-EU regions).
Containers: push images to an in-region ECR and update deployment manifests. Ensure CI pipelines publish to the sovereign ECR.
Object storage: replicate S3 objects to the sovereign-region S3 using replication configured to target only in-region buckets. Disable cross-region replication unless the destination is another approved sovereign region.
Files and archives: use secure transfer agents or partner accelerators, ensuring encryption and in-region landing zones.

Phase 8 — Application migration and CI/CD

Parameterize IaC templates (Terraform/CloudFormation) for sovereign-region settings (account IDs, region codes, endpoints).
Deploy CI/CD pipelines in-region where possible (build servers, runners) or ensure artifact storage is in-region and artifacts aren’t pulled from non-resident repos at runtime.
Test service-to-service communications, authentication flows, and latency characteristics. Optimize edge caching or use in-region CDN PoPs if provided.
Document all external endpoints your app calls and ensure permitted outbound paths are in compliance with the DPA and DPIA.

Phase 9 — Cutover, rollback, and validation

Run a staged cutover: shadow traffic, partial routing, and canary releases before full DNS changeover.
Use health checks and synthetic transactions to verify behavior in the sovereign region under load.
Keep a validated rollback path (DNS, routing, and database reverse-replication) for each application for a defined period post-cutover.
Execute a compliance validation checklist: data residency proofs, logs present, keys validated, and no accidental egress.

Phase 10 — Post-migration ops and audits

Schedule recurring audits and automated validation jobs that verify resource locations, KMS key usage, and cross-account accesses.
Run cost optimization and tagging audits — sovereign environments can have distinct pricing and network cost patterns.
Create an incident response playbook specific to the sovereign region including legal notification steps for cross-border requests.

Architecture changes you must make (practical specifics)

1. Split management and data planes

Put the management console and high-privilege identities in a minimal, tightly controlled management account. Do not use this management account to host production data. For logging, create a dedicated in-region logging account so all audit trails remain inside the sovereign boundary.

2. In-region KMS and key lifecycle

Create KMS keys in the sovereign region and bind them to your accounts. If your security policy requires external key custody, use CloudHSM or an approved XKS-supported HSM that resides inside the EU region. Ensure automated key rotation and strict IAM policies that limit key usage to in-region principals.

3. Network egress prevention

Replace broad internet access with explicit proxy/NAT and private endpoints. Use VPC endpoints for AWS APIs and services. Put network firewalls and egress filters at the transit layer to ensure no traffic leaves the sovereign region unintentionally.

4. Data replication and backup controls

Switch backup and replication targets to in-region services. Disable automated cross-region replication and snapshot copying by default. If cross-border replication is occasionally needed for specific workloads, codify the exceptions with approval workflows and technical enforcement controls (SCPs and guardrails).

DNS, domain and certificate considerations

Keep authoritative DNS records with your chosen registrar, but use conditional forwarding and private hosted zones inside the sovereign region for internal records.
Use in-region certificate authorities (ACM Private CA) or an approved EU CA for private certificates. Maintain certificate logs in-region.
Ensure TTLs are managed during cutover to minimize failover complexity and exposure.

Migration tooling and automation recommendations

Infrastructure as Code (IaC): Centralize Terraform modules or CloudFormation stacks with region-aware variables. Version and scan IaC for region leakage.
CI/CD: Use self-hosted runners inside the sovereign region or CI tools offered inside-region to build and sign artifacts.
Data transfer: AWS DMS, Storage Gateway, or partner data-migration appliances. For bulk datasets use secure seeding via partner networks or physical appliances (if supported).
Testing: Use chaos and load testing inside the sovereign region to ensure performance parity with previous deployments.

Operational and cost considerations

Sovereign regions may have different pricing models and available instance types. Expect some services or features to be introduced later in the sovereign region lifecycle. Budget for potentially higher network and data transfer costs and test autoscaling behaviour under realistic traffic shapes.

Case study (anonymized): European payments platform

A major EU payments provider migrated its payment authorization and ledger systems to the AWS European Sovereign Cloud in Q1 2026. Key steps they took: established a separate AWS Organization OU, created a management account with strict SCPs, deployed an in-region Transit Gateway, used Direct Connect to a local carrier, and migrated databases using DMS with CDC. They kept all encryption keys in CloudHSM instances in-region and deployed a dedicated SIEM cluster inside the sovereign region to ingest CloudTrail and VPC Flow Logs. Outcome: reduced regulatory friction during audits, eliminated cross-border data transfer exceptions, and retained latency-sensitive performance by leveraging local on-ramps.

Common pitfalls and how to avoid them

Assuming global configuration equals global residency — check resource metadata and snapshots.
Replicating logs or metrics to a central non-EU analytics platform without approval — build in-region analytics or ensure export controls are in place.
Using vanilla CI/CD pipelines hosted outside the EU — move runners or artifact storage to the sovereign region.
Not verifying that managed services (e.g., certain AWS SaaS features) are available in the sovereign region — create a service-availability matrix early.

2026 trends and what to expect next

Through late 2025 and early 2026, the pattern is clear: cloud providers will continue shipping sovereign-region capabilities and contractual assurances. Expect increased parity over 2026 as more managed services are made available in sovereign regions and richer tooling appears for cross-boundary controls. Also expect EU regulatory guidance to provide more granular expectations around technical measures for data residency and government access transparency — make sure your legal and compliance teams track updates and that your architecture can adapt.

Actionable takeaways

Start with a complete data-flow map and DPIA. Without this, you can't scope the migration accurately.
Keep all audit logs, keys and backups in-region and restrict cross-region replication by default.
Design accounts and SCPs to prevent accidental resource creation outside the sovereign region.
Test connectivity with local telcos and use private on-ramps to avoid public internet exposure and reduce latency.
Use infrastructure-as-code and CI/CD pipelines that are region-aware, and validate every artifact and secret is resident before cutover.

"Treat the sovereign-region migration as much a legal and telecom project as it is a cloud engineering one." — Recommended approach from our migration playbook

Checklist summary (copyable)

Form cross-functional team and define success criteria
Complete inventory and data classification
Secure contractual sovereign assurances and update DPIA
Build account structure and SCP guardrails
Design in-region network: transit gateway, private endpoints, egress filtering
Deploy in-region KMS/CloudHSM and secrets management
Centralize logging and SIEM in-region
Migrate data using DMS/replication/secure transport
Cut over with canary and rollback plans
Operate with periodic residency audits and cost governance

Final thoughts and recommended next steps

Moving sensitive workloads to the AWS European Sovereign Cloud is a strategic step that reduces regulatory friction and strengthens control over data and access. But it requires deliberate architectural changes and legal coordination. Start with a risk-based inventory, lock down account and network separation, and keep all audit trails and keys in-region. Expect some service gaps early on in 2026, so plan for temporary workarounds and prioritize the workloads that most benefit from sovereign assurances.

Call to action

Ready to plan your migration? Download our EU Sovereign Migration Runbook (workshop template, IaC snippets, legal checklist) or schedule a migration workshop with our cloud architects to produce a custom migration plan and cost estimate. For teams that need hands-on help, we run a two-week assessment that delivers an inventory, DPIA update, network design, and validated cutover plan tailored to your environment.

various

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