Synchronisation between Outlook and Teams calendars

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Currently I have parked my company's domain in Office 365 Business, yet we do not use Exchange as main email server - mail is hosted on our chosen provider's server. So: an user has Outlook set up with IMAP/SMTP connection to our server with account e.g. They also use their Office365 and Teams using accounts that are created using the same email (


I would like my users to have their calendar synced between Outlook and Teams. The main email server is not on Exchange. So, if I think correctly, Teams user gets their calendar data from their own Exchange server data. Thus, I could simply sync calendar in Outlook with calendar on Exchange. Does Exchange provide for CalDav or similar protocol to do it?


Other way I thought about it, I could also sync Exchange calendar (or directly the Teams calendar) and Outlook calendar with my main email server's CalDav/CardDav so that the "main host" of the calendar would be my main server. I just couldn't figure out how to do it.


In the attachment there's some graphical representation of my ideas. I did try to figure it out but cannot really make it work.



My regards! Stay safe and wash your hands!


3 Replies


here is the details about how the Microsoft Teams calendar works 


besides this is a good article about how the calendars works without exchange I did saw the graphic you crates it does make sense but I am not sure if you will be to do it but still doesn’t hurts to give it a try as MS Teams requires Exchange! 



Teams simply fetches the data directly out of the user's Exchange mailbox, there's no such thing as "teams calendar". So for your scenario to work, your users needs to have mailboxes created in O365, at which point you might as well just replace your current mail solution with Exchange Online.

@Vasil Michev and this is why Google is running circles around Microsoft. 
I WANT to like Micorsoft ecosystem, but it HURTS at every turn.
This is not it.