Switch from Fastmail to Posteo: step by step

How to move your mail, contacts and address from Fastmail to Posteo without losing anything. Most moves take an evening to set up, then a few weeks of forwarding.

Moving fromGmailOutlook.comiCloud MailProton MailFastmailTutamailbox.orgPosteoZoho MailGoogle WorkspaceMicrosoft 365 BusinessMailfenceStartMailRunboxAnother providerMoving toGmailOutlook.comiCloud MailProton MailFastmailTutamailbox.orgPosteoZoho MailGoogle WorkspaceMicrosoft 365 BusinessMailfenceStartMailRunboxAnother provider

Show me the stepsCompare them side by side

1. Before you start

   • Check where your address lives. If it ends in @fastmail.com, it belongs to Fastmail and stays there: you'll forward your mail and tell people your new address. If it's on your own domain, like you@yourname.co.uk, it comes with you: you'll change a few DNS settings.
   • Check the space you need. See how much mail you have in Fastmail, and compare it with Posteo's plans (the cheapest is Posteo, €1 a month, with 4 GB).
   • Read the small print. Posteo's page covers exporting, cancelling and refunds under "Before you sign up".

2. Open your Posteo account

   Sign up on Posteo's website (No, €1 a month from the start), and turn on two-step sign-in straight away. You'll find the link on Posteo's page: Posteo.

3. Bring your mail across

   Use Posteo's importer. Posteo's free migration service copies up to three accounts, with their folders, from any provider that allows IMAP. Open Settings, then My account, then Posteo migration service. Posteo's guide ↗

   Your old mail stays where it is while it's copied, so nothing is lost if you need to start again.

4. Move your contacts and calendar

   Export your contacts as a .vcf file and each calendar as an .ics file from Fastmail, then import them into Posteo. Most providers have both options in their contacts and calendar settings. Posteo can copy your address book automatically from Gmail, iCloud, Microsoft, Yahoo, AOL, GMX and WEB.DE. Posteo's guide ↗

5. Keep your @fastmail.com address working

   1. Forward new mail. Look in Fastmail's settings for automatic forwarding, and add your new address.
   2. Tell people. Send your new address to the people who matter, and add it to your email signature.
   3. Update your sign-ins. Change the email address on your bank, shopping, social and work accounts. A password manager's list of saved sign-ins is the quickest checklist.
   4. Keep the old account open for a while. Mail will keep arriving there for months. Sign in now and then so it isn't closed for not being used.

6. Check everything arrived

   • Compare the number of emails in each folder on both sides.
   • Send a test email to your new address from another account, and reply to it.
   • Check that mail forwarded from Fastmail is arriving, and isn't going to spam.

7. Close Fastmail, when you're ready

   Wait at least a month, until nothing new arrives there. On a free account you can leave it open with forwarding on instead. Before you close a paid account, download a last copy of your mail.

   • Cancelling: Change plans or cancel at any time.
   • Refunds: Refunds are at Fastmail's discretion; they don't have to refund prepaid fees if you stop using it.

   From Fastmail's page: Fastmail.

I checked the providers' help pages on 24 October 2026. Menus move, so if a step doesn't match what you see, tell me and I'll update it.

Moving to Posteo from somewhere else? Gmail to Posteo · Outlook.com to Posteo · iCloud Mail to Posteo · Proton Mail to Posteo · Tuta to Posteo · mailbox.org to Posteo · All switching guides