Cross-org free/busy between one -on-prem org and another hybrid org

Copper Contributor

Hi. Could anyone advise on cross-org free/busy calendar sharing between two organisations - where one is on-premises, and the other is hybrid?  Will a user in the on-prem org be able to see free/busy information for all users in the other organisation - some on-prem, and some on-line?  Any article I can refer to?  Thank you.

3 Replies

HI@GarWallis ,


The below links will help you to share your calendar outside organization.


I hope this is informative.






@MDadarkar , thanks for replying.  However, your article reference doesn't address the hybrid environment.


For anyone who is interested, I found this reference which does seem to understand and address the issue of Cross-org/Inter-org Calendar Free/Busy sharing - The Hybrid Mesh - Microsoft Tech Community


Hi @GarWallis ,


Please try these PowerShell commands,.



Get-Mailbox YourMailbox | fl *sharing*

Get-SharingPolicy -Identity "Default Sharing Policy"

******* Creates the sharing policy "PolicyName" for two different federated domains ( and with different sharing actions configured for each domain


New-SharingPolicy -Name "PolicyName" -Domains ' CalendarSharingFreeBusyReviewer', ' CalendarSharingFreeBusyDetail' -Enabled $True


*********This example modifies the sharing policy for the non-federated Anonymous domain.
This policy allows users in the Anonymous domain to see your users' detailed calendar availability (free/busy) information. .


New-SharingPolicy -Name "Non-Fed_External" -Domains 'Anonymous: CalendarSharingFreeBusyDetail' -Enabled $true


*****************Set SharingPolicy on user
Get-Mailbox -Identity "YourMailbox" | Set-Mailbox -SharingPolicy "PolicyName"

***************Adding a domain to an existing policy (you must include any previously included domains.)

Set-SharingPolicy -Identity "PolicyName" -Domains ' CalendarSharingFreeBusySimple', ' CalendarSharingFreeBusyReviewer'

Get-Mailbox -ResultSize unlimited | Where {$_.SharingPolicy -eq "PolicyName"} | format-table Alias,EmailAddresses


*********Enable Sharing Policy
Set-SharingPolicy -Identity "PolicyName" -Enabled $True


I hope this is informative.