Recently we were helping a client plan their migration from Microsoft Exchange to Google Apps. The customer requested that we investigate how their OS X users were going to be able to use Google Calendars with iCal locally on their Macs.

As a Google Apps provider, we were happy to work with them to develop procedures that would work for their users with minimal impact on their current work practices. We began researching but were frustrated at first with what we found. We quickly discovered this helpful Google article, but it didn’t include any instructions on how to add additional calendars other than your own primary calendar.

The critical piece of missing information was how to build the CalDAV server address for the all the calendars you have set up in Google Apps. It is important to remember that all of the sharing and setting of permissions for calendars are controlled by the web interface. You will need to go into the settings panel for each calendar to find the Calendar ID for each calendar you wish to add.

The CalDAV address for your primary calendar is always https://www.google.com/calendar/dav/YOUREMAIL@DOMAIN.COM/user where your Google Apps account replaces YOUREMAIL@DOMAIN.COM. On the settings page of each of your calendars there is a section labeled Calendar Adress. To the right of the XML ICAL and HTML buttons you will see the Calendar ID. The CalDAV server address you will use when configuring iCal to sync with the Google Apps servers is https://www.google.com/calendar/dav/{CalendarID}/user.

It would be nice if Outlook could consume CalDAV natively like iCal which would make working with multiple Google Calendars as easy as this in Windows.

Detailed step-by-step instructions are in the full version of this blog post below.

To configure a calendar in iCal to sync with Google Apps using CalDAV

1) The unique Calendar ID needed for the account url is only available through Google Calendar settings. Select the small down arrow next to the calendar that you are importing and select Calendar Settings.

2) This will bring up a page with details for that calendar, scroll all the way to the bottom to the section labeled Calendar Address: and copy the Calendar ID:

3) Open iCal and go to Preferences.

4) Once you click Add, the calendar will begin syncing in iCal, but before you close the Accounts window, make sure to set the Refresh calendar to a desirable time:

Troubleshooting Tips

This error simply means that the password or username was mistyped and needs to be corrected. Ensure that you are using your full Google Apps email address and your Google Apps password.

This error means that either the URL https://www.google.com/calendar/dav/{CalendarID}/user is incorrect or the Calendar ID is incorrect.