How to Reconnect a Missing Google Calendar on Your Phone
Google Calendar on the web; phone app differences noted · Last checked · Suggest an edit
https://instructions.wiki/google-calendar/reconnect-a-missing-google-calendar-on-your-phone
A calendar that used to appear on your phone is gone, or a shared calendar never showed up. Most of the time it is hidden or not syncing rather than deleted.
Tick the calendar in the Google Calendar app
Open the app and tap the three-line menu. Each account lists its calendars with a checkbox. If the calendar is there but unticked, tick it and its events return. If the account shows only a few calendars, tap Show more to reveal the rest.
Turn on sync for that calendar
From the same menu, scroll down and tap Settings. Tap the calendar under its account and make sure Sync is on. A calendar with sync off appears in the list but never downloads events. Pull down on the calendar view to refresh after changing it.
Enable the calendar on the web if it is not listed
Open calendar.google.com on a computer and check that the calendar appears under My calendars or Other calendars. A calendar shared with you must be accepted there, from the invitation email or Settings, Add calendar, before it exists on the phone at all. Once it is listed on the web, close and reopen the app; it appears under the account after a few minutes.
Turn on Calendars for the account in the iPhone Calendar app
If you use Apple's Calendar app with a Google account, open Settings, Apps, Calendar, Accounts, tap the Google account, and turn Calendars on. Then open the Calendar app, tap Calendars at the bottom, and tick the missing calendar. Shared calendars sometimes need the Google Calendar app or the web sync page to be enabled before Apple's app can see them.
Turn on account sync on Android
Open Settings, Passwords & accounts (or Accounts), tap the Google account, tap Account sync, and make sure Calendar is on. Also check that battery saver or data saver is not blocking background sync for the Calendar app.
If a shared calendar still never appears. It has to be accepted on the web first; the phone apps cannot accept a calendar share. Ask the owner to reshare it if the invitation was lost.
If sync is on but nothing updates. Remove the Google account from the phone and add it again. This clears a stuck sync state and repulls every calendar for that account, and nothing is deleted from Google's side.