Moving Email Between Google Workspace and Microsoft 365

Quick answer: the migration in seven steps

1. Set up the new tenant (Microsoft 365 or Google Workspace), verify your domain and create every user, shared mailbox and alias.
2. Run the migration tool to copy existing email, calendars and contacts while the old system still receives mail.
3. Pick a quiet time, lower the DNS TTL, and switch your MX record to the new provider.
4. Run a final sync (a "delta" pass) to copy anything that arrived during the switch.
5. Update SPF, turn on DKIM and check DMARC for the new provider.
6. Set up phones, laptops and signatures; check shared mailboxes and calendars.
7. Keep the old accounts for a few weeks, then cancel the licences.

If you are still deciding which provider to move to, our comparison of Microsoft 365 and Google Workspace covers prices and features first.

Before you start

• Admin access to both sides: a super admin on Google Workspace and a global admin on Microsoft 365.
• A list of mailboxes: real users, shared inboxes (info@, sales@), aliases and groups. Decide what each becomes on the new side.
• Mailbox sizes. Very large mailboxes take longer and may hit item limits, so plan them separately.
• DNS access to your domain, plus a copy of every current record (MX, SPF, DKIM, DMARC, autodiscover).
• Other services that send as your domain: Xero, Shopify, your website forms, newsletters. They will need SPF or DKIM updates.
• A date: a Friday evening or a public holiday eve usually works well for a small business.

Google Workspace to Microsoft 365

Microsoft's tools run from the Exchange admin center, under Migration. There are two routes, per Microsoft's Google Workspace migration documentation:

• Google Workspace migration (recommended for businesses) moves email plus calendar and contacts.
• IMAP migration moves only email, not calendars or contacts. It also needs each account to create an app password before Microsoft can connect.

You don't have to move everyone at once. Microsoft lets you migrate in batches, and the migration file can list up to 50,000 mailboxes, so a small team usually runs one batch, checks it, then runs the final sync after the MX switch.

Things to plan for on the Microsoft side: Gmail labels become folders, Google Groups need to be recreated as distribution lists or Microsoft 365 groups, and Google Drive files need a separate move to OneDrive or SharePoint.

Microsoft 365 to Google Workspace

Google's data import tool in the Admin console copies Exchange Online email, calendar and contacts into Google Workspace. Google's default data import guide notes that it does not delete or modify the data in Exchange Online.

Google's page on what is imported from Exchange Online lists exceptions worth checking before you start. These are not imported:

• email messages larger than 150 MB;
• draft messages without a From header;
• Outlook categories.

Outlook rules and Gmail filters also work differently, so expect to recreate some rules by hand. OneDrive files and Teams chats have their own import options in the Admin console.

Cut-over day: switching MX without losing email

The MX record tells the world where to deliver email for your domain. Switching it is the moment of risk.

For Singapore businesses that send invoices from Xero or orders from Shopify, check those emails reach customers after the switch. Our guide to why emails go to spam explains the records in detail.

After the move: the clean-up list

1. Set up Outlook or Gmail on each phone and laptop, removing the old account profile.
2. Recreate email signatures, out-of-office messages and shared mailbox access.
3. Check calendar invitations and recurring meetings appear correctly; re-send key ones if needed.
4. Update the email address in your domain registrar, bank and payment accounts if it changed.
5. Turn on MFA for every user on the new system from day one.
6. After everyone confirms their mail is complete, cancel the old licences. If you are leaving Google Workspace and want to keep a former employee's mail, archive or export it first.

Do it yourself or get help?

For one or two people with small mailboxes, the built-in tools and the steps above are usually enough. With shared mailboxes, aliases, several devices per person, or a business that can't afford a day without email, a planned migration saves a lot of stress.

Email Migration (S$390) moves up to 5 mailboxes with folders, contacts and calendars where the source allows, plans the cut-over so no email is lost, and keeps the old mailbox as a backup until you confirm. Extra mailboxes are S$49 each. If the new tenant isn't set up yet, add Business Email Setup (S$249), which includes the MX, SPF, DKIM and DMARC records.