Should a Google Workspace Subsidiary Move Into Our Microsoft 365 Tenant or Stay Hybrid?

Start with an inventory: export the Google users, licenses, last-login data, shared drives, calendars, and external sharing relationships, then reconcile that with existing Entra accounts. If you choose hybrid, set a firm review or retirement date so the second environment doesn’t become permanent by accident.

For users, the biggest disruption usually isn’t the background data copy. It’s the cutover to a different mail client, new file locations, calendar behavior, and unfamiliar workflows. Incremental migration passes and clear training reduce that impact. Also decide in advance when unused Google licenses will be removed so the old environment doesn’t remain an expensive safety net.

The hybrid route can work as an interim design. Google Workspace can be federated with Entra so users authenticate through the identity platform and are subject to Conditional Access, while they continue using Gmail and Drive. I’d pilot that with a small group first, then decide whether mail and files should move later.

Be aware that a Drive migration and an email migration are separate projects. Shared drives, permissions, external collaborators, calendars, and user retraining often cause more trouble than the actual file transfer. A staged approach lets you prove the identity and compliance pieces without forcing every change at once.

If the long-term direction is Microsoft 365, a full migration is probably the cleanest answer. The work is significant, but maintaining two identity and collaboration platforms tends to create ongoing licensing, support, and policy complications. Since you’re handling this alone, bringing in an experienced consultant for planning and cutover would be worthwhile rather than trying to run the entire project alongside normal operations.

I’d be cautious about adopting a third-party MDM solely to postpone a Microsoft 365 migration. It could make sense if you have a genuine cross-platform requirement, but otherwise you may be paying for another management layer while still needing to solve identity integration. A small test group is a good way to compare enrollment, compliance reporting, and support overhead before committing.