Email migration is one of those IT tasks that looks simple on the surface—but gets complex very quickly at scale. In this case study, we walk through how we successfully migrated 70 user mailboxes from one Google Workspace domain to another, with minimal disruption and zero data loss. This real-world project involved cross-domain migration, careful planning, phased execution, and post-migration email forwarding to ensure business continuity. If you’re planning a Google Workspace email migration, this guide will help you understand what’s involved, what to expect, and how to do it right.
Introduction
Email is the backbone of daily business communication. When an organization changes its domain—due to rebranding, mergers, compliance requirements, or regional expansion—email migration becomes a mission-critical project.
A poorly executed migration can lead to lost emails, broken workflows, confused users, and support overload. A well-planned one, however, is almost invisible to end users.
In this blog, we share a real Google Workspace Email Migration Case Study: Moving 70 Users to a New Domain, covering the challenges, approach, tools used, timeline, and best practices. This is written from the perspective of hands-on engineers who manage such migrations regularly—not theory, but practical experience.
Project Overview
Let’s start with the basics of the project.
Scope at a Glance
- Source: Existing Google Workspace (old domain)
- Destination: New Google Workspace (new domain)
- Users migrated: 70 email accounts
- Migration type: Cross-domain Google Workspace to Google Workspace
- Tool used: Google Workspace Data Migration Service
- Duration: Approximately 2 weeks
- Downtime: None
- Post-migration setup: Email forwarding from old domain to new domain
The primary objective was to ensure that all historical email data was preserved while enabling users to transition smoothly to the new domain.
Why the Migration Was Needed
The organization decided to move to a new domain for strategic reasons, including:
- Brand realignment
- Cleaner domain naming
- Improved administrative control
- Long-term scalability
Rather than continuing with aliases or partial setups, the decision was made to perform a clean migration of all user mailboxes to a new Google Workspace tenant.
Key Challenges in This Migration
Every migration comes with its own set of challenges. In this case, the main concerns were:
1. Data Integrity
Each user had years of emails, labels, and folders. Losing even a small percentage of data was not acceptable.
2. User Disruption
The company could not afford email downtime. Business operations had to continue as usual.
3. Cross-Domain Complexity
Unlike same-domain migrations, cross-domain setups require careful identity mapping and validation.
4. Migration Timing
Not all users had the same mailbox size. Some mailboxes were lightweight, while others contained large volumes of data.
Pre-Migration Planning
Good migrations are won or lost during planning.
User & Domain Preparation
Before any data was moved:
- All 70 users were pre-created in the destination Google Workspace
- New email IDs were mapped one-to-one with old accounts
- Admin access was verified on both source and destination tenants
- DNS access was reviewed in advance
This preparation allowed us to migrate without rushing or making last-minute changes.
Migration Strategy
Rather than moving everything at once, we followed a controlled and phased approach.
Why Phased Migration?
- Reduces risk
- Allows testing with early users
- Makes troubleshooting easier
- Avoids performance throttling by Google
Users were grouped based on mailbox size and business priority.
Tool Used: Google Workspace Data Migration Service
For this project, we used Google’s native Data Migration Service.
Why This Tool?
- Built-in and officially supported
- Secure and reliable
- No third-party dependencies
- Fine-grained control over migration batches
It allowed us to migrate:
- Emails
- Labels
- Read/unread status
- Folder structure
Contacts and calendars were handled separately where required.
Step-by-Step Migration Process
Here’s how the actual migration was executed.
Step 1: Authentication & Permissions
Admin access was granted on both tenants, and API permissions were validated to avoid throttling or access issues.
Step 2: User Mapping
Each source email account was mapped to its corresponding destination account in the new domain.
Step 3: Pilot Migration
A small set of users was migrated first to validate:
- Data completeness
- Migration speed
- User experience
This step helped fine-tune the overall process.
Step 4: Full Migration Execution
Once validated, remaining users were migrated in batches. Larger mailboxes were scheduled during off-peak hours to reduce impact.
Step 5: Delta Sync
Final delta syncs were run to ensure that emails received during the migration window were also transferred.
Email Forwarding Setup
To ensure no email was missed during or after the transition, we configured email forwarding.
How Forwarding Helped
- All incoming emails to the old domain were forwarded to the new domain
- Users could transition gradually
- External senders didn’t need immediate updates
This forwarding was maintained temporarily until the DNS cutover was complete.
Timeline Breakdown
The total duration was around 2 weeks, influenced by:
- Number of users
- Mailbox sizes
- Google API processing limits
Typical Timeline
- Days 1–2: Planning & user setup
- Days 3–5: Pilot migration
- Days 6–12: Batch migrations
- Days 13–14: Final sync & validation
This realistic timeline avoided pressure and ensured accuracy.
User Communication & Support
Technical success alone isn’t enough. Users need clarity.
What We Communicated
- Login instructions for new email accounts
- Password reset guidance
- Timeline expectations
- What to do if something looks missing
Clear communication reduced support tickets and user anxiety.
Post-Migration Validation
After migration, each account was checked for:
- Email count consistency
- Label and folder structure
- Recent emails
- Sending and receiving functionality
Only after verification was the migration considered complete.
Results & Outcome
The project was completed successfully with:
- 100% email data migrated
- Zero email loss
- No business downtime
- Smooth user adoption
The client transitioned fully to the new domain with confidence.
This Google Workspace Email Migration Case Study: Moving 70 Users to a New Domain demonstrates that with the right planning and execution, even large migrations can be seamless.
Best Practices Learned
Here are key takeaways from this project:
- Always pre-create users in the destination tenant
- Use pilot migrations
- Don’t rush DNS changes
- Keep email forwarding active during transition
- Communicate clearly with users
- Validate everything before closing the project
These practices apply to migrations of any size.
When Should You Plan a Similar Migration?
You should consider a structured email migration if:
- You’re changing your business domain
- You’re merging organizations
- You want better control or compliance
- Your current setup is fragmented
Early planning saves time, money, and stress.
Conclusion
Email migrations don’t have to be painful. With the right tools, experience, and planning, they can be smooth and almost invisible to users.
This Google Workspace Email Migration Case Study: Moving 70 Users to a New Domain shows how a structured approach, phased execution, and proper communication lead to success.If your organization is planning a similar move, treat it as a project—not just a task. The results will speak for themselves.
Frequently Asked Questions:
1: What is a Google Workspace email migration?
A Google Workspace email migration is the process of transferring emails, folders, and labels from one Google Workspace account or domain to another while preserving data integrity and user access.
2: How long does it take to migrate Google Workspace email accounts?
The migration timeline depends on the number of users and mailbox sizes. For 70 users, a phased Google Workspace email migration typically takes around 1–2 weeks.
3: Will users experience downtime during the migration?
No. With proper planning, phased migration, and email forwarding, users can continue sending and receiving emails without disruption during the Google Workspace migration.
4: Which tool is best for migrating Google Workspace emails?
The Google Workspace Data Migration Service is the most reliable and secure tool for migrating emails between Google Workspace domains, as it is natively supported by Google.
