So what are we using for global shared calendars now in O365 environment?

[thecomputerguy]

The options I know of are:

Employee sharing out a calendar manually - NO
Public Folders Calendar - NO
Shared mailbox calendar - NO Mailbox needed
Teams Group Calendar - Maybe?
Meeting room Calendar - Maybe?

Calendar needs to be accessible on Desktop and Mobile

I'm not sure how well outlook for iOS or Android works with meeting rooms or group calendars

 

[Sky-Knight]

There are multiple ways to share calendars in Microsoft 365. Each method supports different workflows, and the best choice depends on your organization's habits and technical preferences. Below is a breakdown of the main options with their strengths and limitations.

1. Personal Calendar Sharing
   Users can share their own calendars directly from their mailbox. This has been available since early versions of Exchange. It is fast and simple but not reliable long term. If the user leaves the company, the calendar disappears.
2. Shared Mailboxes
   This is a more stable alternative to personal sharing. The mailbox is not tied to any individual and access can be managed centrally. It preserves the familiar Outlook experience and works well for team calendars or resource scheduling such as meeting rooms.
3. Microsoft 365 Groups
   These include a shared calendar and mailbox without requiring full Teams integration. They are lightweight and useful for departments or small teams that need basic collaboration tools.
4. Teams Calendars
   Every Team includes a calendar tab that is backed by a Microsoft 365 Group. This setup provides access to chat, files, tasks, and other collaboration features. It is my preferred option for most modern workflows. Access management is handled by the team owner, which reduces admin overhead. The main challenge is user training. Younger users tend to adapt quickly while older users may need support.
5. SharePoint Calendars
   These are less common but still useful for organizations that rely heavily on custom SharePoint sites. They are not well integrated with Outlook and can be awkward to use, but they serve a purpose in specific scenarios.
6. Planner and Other Integrated Tools
   Planner includes task scheduling that can be displayed on a calendar and shared. It is not a traditional calendar but works well for project-based scheduling. There are also third-party apps in the Microsoft 365 ecosystem that offer similar functionality.

My default recommendations

• Shared Mailbox: Manual setup but familiar for legacy users and easy to manage
• Teams: User-centric, scalable, and low admin overhead. Best suited for collaborative environments

The Outlook mobile app for Android and iOS supports both Teams-based calendars and calendars tied to Shared Mailboxes. In general, both work well, but Shared Mailbox calendars can occasionally behave unpredictably on mobile. Teams calendars tend to be more stable and also appear in the Teams mobile app, which gives users an alternative if they run into issues. If someone gets stuck in Outlook, they can usually switch to Teams and find what they need.

 

[YeOldeStonecat]

Same 2 here...
Shared Mailbox for ...I'd say "most"..for just a pure calendar.
Teams...if there needs to be more collaboration