Office 365 tenant to tenant migration can involve significant costs, depending on the size of the organization and the method chosen. Manual O365 mailbox migration may seem cost-effective initially, but it often leads to hidden expenses due to prolonged downtime, potential data loss, and the need for IT resources. Automated tools, while requiring an upfront investment, can reduce overall costs by streamlining the process and minimizing risks.

When planning your migration, consider factors such as licensing, tool subscriptions, and potential downtime. It is better to proceed with the third party migration services for Office 365 Tenant to Tenant Migration. It can save your time and efforts.