Exchange Online Free/Busy federation between two Office 365 tenants

I have recently tried to establish the GAL Federation between two of my Office 365 Exchange Online tenants to share the Free busy Availability between those domains. I have used the domains and the free one

1) Connect to Exchange Online through PowerShell as an administrator user on one of the domain (

2) Find the existing Federation info between the domains under consideration. Substitute the domain name when asked as below:

Get-FederationInformation -DomainName


3) Create a New Organization Relationship between the domains and set the Free Busy Properties. In this step, I am going to set the FreeBusyAccessLevel as ‘AvailabilityOnly’

Get-FederationInformation -DomainName “Domain Name” | New-OrganizationRelationship -Name ‘Federaion’ -Enabled $true -FreeBusyAccessEnabled $true -FreeBusyAccessLevel ‘AvailabilityOnly’ -FreeBusyAccessScope $null


4) Now check the Scheduling Assistant in owa or outlook and see it has shared as below: I have tried to check the availability info of a mailbox located in the federated domain


5) Similarly, you may also set the ‘FreeBusyAccessLlevel’ as ‘LimitedDetails’ for the existing OrganizationRelationship as below:

Set-OrganizationRelationship ‘Test-Federation’ -FreeBusyAccessLevel LimitedDetails


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8 thoughts on “Exchange Online Free/Busy federation between two Office 365 tenants

  1. Hi, is there a possibility to do the same between O365 tenant (hybrid coexistence mode) and Exchange 2010 from another forest? Thank you

  2. Hello,

    What if if want more – share global address book, skype for bussiness users, sharepoint access in both tenants?

  3. We need to be able to share Conferensrooms between 2 tennants. With Contact object for rooms in the other tennant the ad a room feature in Outlook is inconsistent, any suggestions on how to solve this?

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