ICS Calendars

ICS calendars, also called web calendars or subscribed calendars, are calendars you follow through a public URL. Holiday calendars, sports schedules, team rosters and feeds exported from other tools are usually ICS calendars.

OneCal does not subscribe to ICS URLs directly. You add the ICS calendar to your Google or Microsoft account first, then import that calendar account into OneCal.

Import an ICS calendar into OneCal

1. Subscribe to the ICS URL in Google Calendar or Outlook, using the provider's own flow (Add calendar → From URL in Google Calendar, Add calendar → Subscribe from web in Outlook).
2. Connect that calendar account to OneCal. See Connect Google Calendar or Connect Outlook Calendar. If the account is already connected, connect it again to import the calendars you don't have in OneCal yet.
3. Select the ICS calendar on the import screen and click Import Calendars.

Once imported, the ICS calendar behaves like any other calendar in OneCal. Its events appear in your Unified Calendar View, it can be the source of a calendar sync, and booking links can read availability from it.

ICS calendars are read-only

Google and Microsoft expose subscribed calendars as read-only, so nothing, including OneCal, can write to them. Anything that needs write access is unavailable:

• Target calendars in a sync: An ICS calendar can be the source of a one-way sync, but never the target, because OneCal has to create clone events on the target. For the same reason it cannot be part of a multi-way sync, where every calendar is both a source and a target.
• Booking link calendars: An ICS calendar cannot be the calendar a booking link adds its bookings to. It can still be used to check availability, so schedulers are not offered times that clash with its events.
• Creating and modifying events: You cannot create, edit or delete events on an ICS calendar from the Unified Calendar View.