Can anyone in my groups see my "Only You" calendar?

Your Only You group is private by default — people in your other groups can’t see the calendars, event details, or chat inside your Only You group.

Two important exceptions

1) If you share your Only You group with someone

Legacy Only You groups now function like standard groups, which means you can optionally invite others to join them.

If you add someone to your Only You group, they’ll be able to access what’s shared inside that group (like any other group).

2) Availability Sharing (busy time only)

If you’ve enabled Availability Sharing between groups, members of those groups may be able to see your busy time blocks (free/busy) for scheduling. This does not reveal event titles, notes, locations, or chat contents from your Only You group.