Tenant-to-tenant migration
Move people, data and devices between Microsoft 365 tenants without losing a day of work.
Acquisitions, divestitures, rebrands and consolidations all end in the same job: moving identities, mailboxes, files, Teams and devices from one tenant to another while the business keeps running. We plan it against your deal dates and cut over in waves people barely notice.
Start with tenant migration readiness
When you need it
- Acquisitions and mergers: bringing an acquired business into your tenant
- Divestitures and tenant splits: carving a business out into a new tenant under a transitional services agreement
- Rebrands and domain changes that need a new tenant
- Consolidating several tenants built up over years of growth
What moves
- Identities and groups, with a plan for how people sign in on the day
- Mailboxes, archives, calendars and shared mailboxes
- OneDrive and SharePoint content, with permissions mapped to the new tenant
- Teams, channels and chats, where the tooling supports it
- Devices, re-enrolled into Intune in the target tenant
- Domains, cut over with email routing planned to the hour
- Licences, consolidated so you stop paying twice
How it runs
- Readiness: inventory of both tenants, data scoping, a Day 1 plan and a migration plan with waves and dates. This is the tenant migration readiness assessment, or it is built into the project.
- Coexistence: free/busy, a shared global address list, cross-tenant access and synchronisation, and Teams federation, so people can work together before they move.
- Pilot: a small group moved end to end, to prove the method and the tooling.
- Waves: users, data and devices moved in groups that keep teams together, each with communications and support on the day.
- Cutover and decommission: domains moved, licences consolidated, the old tenant retired once retention and legal hold obligations are met.
What usually breaks, and how we avoid it
A domain can only be verified in one tenant at a time, so the domain move is a planned window with email routing worked out in advance. Devices need re-enrolling, and Autopilot registrations have to move with them. Shared links, Teams meeting links and app integrations point at the old tenant. Each of these is in the plan before the first wave.
Tooling
Tooling is vendor-neutral and chosen per workload. Microsoft's native cross-tenant migration suits some workloads; third-party tools suit others, particularly Teams chat and large SharePoint estates. You get the reasons for each choice in writing.
Experience behind it
Before North Ark, our founder's work included SharePoint migrations, Microsoft 365 compliance projects and data migrations of 20TB and more. Every migration we run is scripted and documented, and the scripts stay with you.
Questions buyers ask
How long does a tenant-to-tenant migration take?
It depends on the number of users, the volume of data and the deal dates. Readiness usually takes two to four weeks, and the migration is planned in waves from there.
Can people work together before they move?
Yes. Coexistence gives shared calendars, a shared address list and Teams chat between tenants while the migration runs.
Will users need new passwords or devices?
They sign in to the new tenant with a new or migrated identity, and devices are re-enrolled rather than replaced. We plan the day so each group knows what to expect.
What happens to email during the domain cutover?
The domain move is scheduled in a window with mail routing planned in advance, so mail is queued and delivered rather than lost.
Can you work to deal dates and a transitional services agreement?
Yes. The plan is built backwards from Day 1 and the TSA exit date, with the decisions each one needs.
Who pays for migration tooling?
Tool licences are part of the project quote and passed through at cost, with the choice explained per workload.
Start a conversation
Plan the move before the deal date sets it for you.
Tell us about the tenants involved and the dates you are working to.
Talk to an Engineer