If you want to know how to migrate email from one provider to another, the short version is this: create the new mailboxes first, copy the old mail over with an IMAP import, and only then switch your domain's mail records. Do it in that order and you lose nothing.
Quick answer
- Set up the new mailbox before you touch the old one.
- Use the new provider's built-in importer if it has one. It is the easiest path.
- No importer? Add both accounts to one email app and copy folders over with IMAP.
- Copy mail first. Change your domain's MX records last.
- Contacts and calendars usually move separately from mail.
I wrote this from the official Google and Microsoft help pages and one hosting guide. I did not run these migrations myself. This is general information, not professional advice.
Which method should you use?
Pick the method by your situation. Here is how I would sort it.
| Your situation | Best method |
|---|
| One personal mailbox | Built-in importer or an email app |
| A few business users | Admin console IMAP import |
| Many users, custom domain | CSV-based batch import |
This table is my own judgment, built from the sources below.
Step 1. Prepare before you move anything
Do the boring work first. It prevents most problems.
- List every mailbox you need to move, including shared ones.
- Check how big each mailbox is.
- Tell your users the cutover date in advance.
- Back up the old mailbox. Export it to a file if your provider allows it.
- Write down the old provider's IMAP server name. Google's help page lists common ones.
Hostinger's guide also says to back up first and create matching accounts on the new service before you move messages.
Step 2. Create the mailboxes on the new provider
The mailbox has to exist before mail can land in it. Microsoft says this plainly for Microsoft 365: create the users and assign licenses first, because the mailboxes must exist to use IMAP migration.
If you are an individual user, just create the new account. Then look in its settings for an import option.
Step 3. Copy the old mail over with IMAP
IMAP is the common language most providers speak. It lets one service pull mail from another.
Option A. Use the built-in importer
Many providers include one. Fastmail, for example, has an IMAP importer in its settings, according to a search summary I read. You enter the old server and login, and it pulls the mail across.
Option B. Google Workspace admin import
Google's help page for importing from an IMAP account gives these steps, which I read on 2026-11-09:
- Sign in to the Admin console as a super administrator.
- Go to Data, then Data import and export, then Data import.
- Under IMAP, click Import.
- Pick or type your IMAP server address, then click Test connection.
- Map each old address to a Workspace user, with the old password.
Google's page lists IMAP server names for many providers, such as imap.fastmail.com and imap.mail.yahoo.com. It also says you cannot copy one IMAP user into several Workspace users. Some servers need an app-specific password.
Option C. Microsoft 365 IMAP migration
Microsoft Learn lists limits worth knowing before you start (read 2026-11-09):
- It moves mail folders only. It does not move contacts, calendar items, or tasks.
- It moves at most 500,000 items per mailbox, newest first.
- The biggest single message it can move is 35 MB.
Microsoft also recommends turning off archive and retention policies first. Otherwise messages those policies removed can show up as "missing" and look like data loss.
Option D. Do it by hand in an email app
If neither side has an importer, add both accounts to one desktop email app. Then drag folders from the old account to the new one. It works, but it is slow for large mailboxes. Hostinger describes this as the manual fallback when both accounts support IMAP.
Step 4. Move contacts and calendars
Mail is only part of the job. Microsoft's IMAP migration does not carry contacts or calendars, so plan for them separately.
- Export contacts as a CSV or vCard file, then import them to the new service.
- Export your calendar as an ICS file and import it.
The exact menu names differ by provider, so check the help page of the one you use.
Step 5. Switch your domain's mail records
This step only applies if you use your own domain, such as you@yourcompany.com. Skip it for a free Gmail or Outlook address.
Your domain's MX records tell the world where to deliver your mail. Change them to the new provider's values, and new mail starts arriving there. Do this after the bulk copy is done, then run one more import to catch anything that arrived in between.
Lowering your DNS record's TTL a day ahead can help the change spread faster. That is common practice, not something I verified in these sources.
Step 6. Check everything before you cancel the old account
- Send a test email to the new address from two other accounts.
- Compare folder counts between old and new.
- Open a few old messages with attachments.
- Reset your phone and laptop mail apps to the new account.
- Keep the old account alive for at least a few weeks.
If you also changed devices, my guide on how to transfer data to a new computer covers the rest of the move.
Common mistakes
- Switching MX records first. New mail then goes to an empty mailbox while old mail sits behind.
- Forgetting two-step verification. The importer may need an app password. See my guide on setting up two-factor authentication for business.
- Ignoring size limits. Big mailboxes may skip items. Plan a second pass.
- Cancelling the old plan too early. Keep it until you are sure.
After any move, watch your accounts for odd activity. If something looks wrong, read how to recover a hacked business email.
FAQ
Can I migrate email without losing anything?
Mostly yes, if you copy with IMAP and keep the old account until you verify. Items over size limits or removed by retention policies can be skipped, so compare counts afterward.
How long does email migration take?
It depends on mailbox size and the speed of both servers. I did not find an official time figure, so test with one small mailbox first.
Does IMAP migration move contacts and calendars?
Not with Microsoft's IMAP migration, which moves mail folders only. Export and import contacts and calendars separately.
Do I need to change my DNS records?
Only if you use a custom domain. Update the MX records after the bulk copy so new mail goes to the new provider.
Can I move my email from Gmail to another provider?
Usually yes. Gmail supports IMAP, and a new provider's importer can often pull from it. You may need an app password if you use 2-step verification.
Sources
Not confirmed: Fastmail importer details (from a search summary), DNS TTL advice, and Gmail-specific export steps.
Last updated: November 9, 2026
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