Tenant to tenant mail migration from large to small organization

You’re correct the older guidance suggesting an “easy” tenant-to-tenant mail migration is no longer accurate for small organizations.

Microsoft’s native cross-tenant mailbox migration now requires Cross-Tenant User Data Migration, which is typically available only to Enterprise Agreement (EA) customers. Without EA and full admin access in the source tenant, the native method isn’t practical.

In scenarios like yours (splitting from a large organization with limited permissions), PST export/import is slow, manual, and risky, especially without admin rights.

In practice, many small organizations use third-party tools like CloudBik, which don’t require EA licensing and can migrate mail, calendar, and contacts directly between tenants with minimal disruption and no dependency on PSTs.

This is usually the fastest and least disruptive option for small-to-large tenant separation cases.