Clarification on GCCH‑to‑GCCH Tenant Mailbox Migration Support

Juan Alicea Rodriguez 0 Reputation points
2026-09-09T19:52:43.35+00:00

Hello,

I would like to confirm whether Microsoft supports cross‑tenant mailbox migration between two GCCH tenants.

From the documentation, I understand that cross‑cloud migrations (e.g., Commercial <> GCCH) are not supported. However, it is less clear whether migrations are supported within the same government cloud instance (GCCH > GCCH).

If this scenario is supported, could you please advise whether the Cross‑Tenant User Data Migration license is required for each user, and whether these licenses must be procured through an Azure Government authorized reseller or directly via Microsoft EA/EAS channels?

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  1. Jay1 Tran 600 Reputation points Independent Advisor
    2026-09-09T20:55:17.5266667+00:00

    Hi Juan,

    Thank you for reaching out.

    Based on current Microsoft public documentation, there is no explicit statement that native cross-tenant mailbox migration between two GCCH tenants is unsupported. However, the feature and its required Cross-Tenant User Data Migration license are documented only for commercial Microsoft 365 tenants. There is no equivalent documentation, licensing path, or support statement for GCC High (GCCH).

    Therefore, while not explicitly excluded in writing, the feature is not currently available for GCCH tenants in practice. The Cross-Tenant User Data Migration license is not offered through Azure Government authorized resellers or EA/EAS for GCCH, because the underlying service is commercial-only.

    For a definitive confirmation, I recommend opening a support ticket with Microsoft Support directly through the Microsoft 365 Admin Center. They can provide the official position for GCCH-to-GCCH migration and advise if any exceptions or future roadmap exist.

    For guidance on how to request support in the admin center, please refer to: Get support - Microsoft 365 admin.      

    Hope you're able to get this resolved soon. Any updates would be greatly appreciated.

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