This article describes how to use Google calendars together with Thunderbird. You can use Google calendars in two ways. You can either use a read/write calendar, with both read and write access or read only (also known as view only) access to public calendars.

How to add read/write Google calendars

First, select the Google calendars you want to synchronize with Thunderbird

Before you start the steps below, go to https://calendar.google.com/calendar/syncselect and select the calendars you want to synchronize. If you do not select them in this step, they will not appear in Thunderbird in the next step.

Second, add your read/write calendars

1. Click ≡ > New Account > Calendar > On the Network > Next
2. Enter your Google account address in the Username field and then click Find Calendars. This should start the Google sign-in flow and then present you with a list of calendars you can subcribe to.
3. Tick the calendars you would like to synchronize and then click Subscribe.

In case of errors, please retry at least once. You should be able to select any of the calendars you enabled in the previous step and add them to Thunderbird.

How to add read only Google calendars

If you only need read-access to a Google calendar, you can use the link of the public ICS file which is provided by Google, as indicated on this Google Help article: View from other applications