Adding Global Calender

Hi,  

For your requirement of having a centralized holiday calendar that is easily accessible and ideally auto-added to everyone’s Outlook, the best approach in Microsoft 365 is to use a shared calendar backed by a shared mailbox. 

I suggest creating a shared mailbox (e.g., ******@yourcompany.com) and using its calendar to maintain all regional holidays. 

• The calendar can be centrally managed by your team 
• Permissions can be assigned to all employees (via a security group) 
• The calendar typically auto-appears in Outlook (especially desktop clients) once access is granted 
• Users can view all global holidays in one place without needing to manually add them 

The high-level setup are as follow: 

• Create a shared mailbox in Microsoft 365 
• Assign Reviewer (read-only) access to all employees or a global security group 
• Populate the calendar with regional holidays (you can import via Excel or .ICS files) 

Please note: 

• In Outlook Desktop, the calendar usually appears automatically 
• In Outlook Web/Mobile, users may need to open it once, but it will remain available afterward 
• If you require a fully enforced auto-add (no user action at all), this can be achieved with an additional automated deployment using PowerShell or Intune policies 

You could also use a Microsoft 365 Group calendar, but from experience, the shared mailbox approach gives better visibility and a more familiar calendar experience. 

You may find further guidance here:

• Share calendar and contacts in Microsoft 365 
• About shared mailboxes, shared folders, and shared calendars in Outlook 
• Create a shared mailbox 
• How to Set Up a Shared Calendar for All Users in Microsoft 365(Please note that this information is shared solely for your convenience. The referenced sites are not managed or maintained by independent advisors, and therefore I cannot guarantee the accuracy, security, or suitability of any software or content available on those sites. I recommend reviewing all information carefully and ensuring you fully understand any potential risks before following suggestions from the provided links.) 

I hope this information is useful. Additionally, as other users have raised similar concerns and may not be aware of where to share their feedback, I hope this response helps clarify the situation and suggests a potential next step. Highlighting this information can make it more visible to others in the community who may be facing the same issue, making it easier for them to find guidance and contribute their feedback as well. 

Thank you again for your time and for raising this important usability concern. If you have any further questions or need additional assistance, please don’t hesitate to reach out. 

I look forward to your thoughts on this. 

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