Migrate business email and calendar from Google Workspace

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You can use an admin-ran migration to Exchange Online from Google Workspace. You can migrate the mail either all at once, or in stages. The following steps show how to migrate the email data at once. For more information, see Perform a G Suite migration.

The migration process takes several steps and can take from several hours to a couple of days depending on the amount of data you are migrating.

Create a Google Service Account

  1. Using a Chrome browser, sign into your Google Workspace admin console at admin.google.com.

  2. In a new tab or window, navigate to the Service Accounts page.

  3. Select Create project, name the project, and choose Create.

  4. Select Create service account, enter a name, choose Create and then Done.

  5. Open the Actions menu, select Edit, and take note of the Unique ID. You’ll need this ID later in the process.

  6. Open the Show domain-wide delegation section.

  7. Select Enable G Suite Domain-wide Delegation, enter a product name for the consent screen, and choose Save.


    The product name is not used by the migration process, but is needed to save in the dialog.

  8. Open the Actions menu again and select Create key.

  9. Choose JSON, then Create.

    The private key is saved to the download folder on your device.

  10. Select Close.

Enable API usage for the project

  1. Navigate to the APIs page.
  2. In the search bar, enter Gmail API.
  3. Select it and then choose Enable.
  4. Repeat this process for Google Calendar API, People API, and Contacts API.

Grant access to the service account

  1. Return to the Google Workspace admin console.

  2. Select Security, scroll down, and open API controls.

  3. Scroll down and select Manage Domain-wide Delegation.

  4. Select Add new and enter the Client ID you made note of earlier.

  5. Then enter the OAuth scopes for Google APIs. These are available at aka.ms/GoogleWorkspaceMigration in step 5 and are:


  6. Choose Authorize.

Create a sub-domain for mail going to Microsoft 365

  1. Return to the Google Workspace admin console.

  2. Select Domains, Manage domains, then, Add a domain alias.

  3. Enter a domain alias like m365.contoso.com.

  4. Then select Continue and verify domain ownership.

    Domain verification usually takes just a few minutes, but it can take up to 48 hours.

  5. Go to the Microsoft 365 admin center.

  6. In the Microsoft 365 admin center, in the left nav, select Show all > Settings > Domains, and then Add domain.

  7. Enter the subdomain you previously created, then select Use this domain.

  8. To connect the domain, select Continue.

  9. Scroll down and take note of the MX records, CNAME records, and TXT records.

  10. Return to the Google admin console.

  11. Select Domains, select Manage domains, Verify Details and then, Manage domain.

  12. In the left nav, choose DNS and scroll down to Custom resource records.

  13. Open the record type dropdown and select MX, enter or copy and paste the MX record information you previously noted,then choose Add.

  14. Repeat the process for the CNAME record and the TXT record.

    It may take some time for these changes to take effect.

  15. Return to where you left off in Microsoft 365 admin center, and select Continue.

Your domain is now set up.

Create email aliases in Microsoft 365

Before migration can begin, you need to create email aliases for your users with the new subdomain.

  1. To start the next step, in the Add Domains wizard in the Microsoft 365 admin center, select Go to Active users.

  2. Select a user, then, Manage username and email.

  3. From the Domains dropdown, select the subdomain you previously created.

  4. Enter a username, select Add, Save changes, and close the window.

    Repeat this process for each user.

Start the migration process

Once you’ve finished, you’re ready to migrate.

  1. In the left nav of the Microsoft 365 admin center, scroll down to Admin centers,and select Exchange.

  2. Under recipients, choose migration, select New, Migrate to Exchange Online, choose G Suite migration, and then Next.

  3. Create a CSV file with a list of the mailboxes you want to migrate. Make sure the file follows this format:


    For details see aka.ms/GoogleWorkspaceMigration.

  4. Select Choose File, navigate to the CSV file, choose it, select Open, then Next.

  5. Verify the admin email address you want to use for testing.

  6. Select Choose File, navigate to the JSON file you created earlier (usually in the Downloads folder on your computer), choose it, select Open, then Next.

  7. Enter a name in the New migration batch name field.

  8. Enter the subdomain you created in the Target delivery domain field, select Next, and then New.

  9. Once the information is saved, select OK.

    You can now view the status of your migration.

  10. After some time has passed, depending on how many users you are migrating, select Refresh.

  11. Once the status has changed to Synced, select Complete this migration batch,then Yes.

  12. Once the process is complete, your status will change to Completed.

  13. If you want, you can select View details for more information about the migration.

  14. Select Close.

  15. Open Outlook to verify that all the emails from Google Workspace were successfully migrated. You can repeat this for calendar items and contacts as well.