Why don’t appointments always sync between my iPad, iPhone, and Mac

Hello Kygypsy,

Thank you for using Apple Support Communities.

Make sure to restart all devices involved. Sometimes a restart can help resolve sync issues.

If you're using iCloud to sync your calendars, here are some steps to follow:

Check if you still need help after each of the steps below. 

1. Check the system status of iCloud Contacts, Calendars, and Reminders.

2. If a reminder isn't showing up on some devices, make sure that you're running the latest iOS, iPadOS, or macOS on each device. Upgraded reminders and shared reminders in iOS 13 or later or macOS Catalina or later aren't compatible with earlier versions of iOS or macOS. Learn more.

3. Make sure that the date and time settings on your iPhone, iPad, iPod touch, Mac, or PC are correct.

4. Make sure that you're signed in to iCloud with the same Apple ID on all of your devices. Then, check that you turned on Contacts, Calendars, and Reminders* in your iCloud settings. 

5. Check your Internet connection. Open Safari and go to www.apple.com. If you can’t open the page, learn what to do.

6. Check that you can access secure websites. Open Safari and go to your Apple ID account page. If the website won't open, contact your Internet service provider for help.

7. Make sure that you haven't exceeded your iCloud storage limit or the storage limits for iCloud Contacts, Calendars, and Reminders. 

Additional information is available here: If your iCloud Contacts, Calendars, or Reminders won’t sync - Apple Support

If you're not using iCloud to sync calendars, make sure that you have the accounts set up on all devices involved:

Set up multiple calendars on iPhone - Apple Support

See multiple calendars at once

To view multiple calendars, tap Calendars at the bottom of the screen, then do any of the following:

•Select the calendars you want to view.

•Tap US Holidays to include national holidays with your events.

•Tap Birthdays to include birthdays from Contacts with your events.

Set a default calendar

You can set one of your calendars as the default calendar. When you add an event using Siri or other apps, it’s added to your default calendar.

1. Go to Settings  > Calendar > Default Calendar.

2. Select the calendar you want to use as your default calendar.

Turn on iCloud, Google, Exchange, or Yahoo calendars

Go to Settings  > Calendar > Accounts > Add Account.

Do any of the following:

1. Tap a mail service (iCloud or Microsoft Exchange, for example), then sign in to your account.

2. Tap Other, tap Add CalDAV Account or Add Subscribed Calendar, then enter your server and account information.

Set up multiple calendars on iPad - Apple Support

Add or delete calendar accounts on Mac - Apple Support

If you're manually syncing from your Mac, these steps will help:

Sync contacts and calendars onto your Mac and iPhone or iPad - Apple Support

If you're using an email service to sync your calendars, you may need to reach out to the email service provider for additional help with sync issues.

Have a good day.