Improved management of secondary calendars via the Calendar API

As previously announced, the new endpoint in the Google Calendar API that allows administrators to programmatically transfer the ownership of secondary calendars is now being rolled out. Its functionality mirrors the data transfer feature currently available in the Admin console by permitting transfers between users in the same organization without sending emails or requiring confirmation from the recipient. Beyond replicating the Admin console functionality, the API provides greater flexibility by allowing administrators to transfer specific, individual secondary calendars.

To help organizations prepare for the upcoming secondary calendar data lifecycle changes, where secondary calendars will follow the lifecycle of their owner, administrators can now programmatically monitor the ownership status of their users’ secondary calendars.

A new filtering option will be available in the CalendarList:list API method that restricts results to return only secondary calendars owned by the organization. When combined with the users.list method of the Admin SDK API, administrators can retrieve a comprehensive list of organization-owned secondary calendars across their users’ calendar lists. The dataOwner field can then be used to verify current ownership status and make any necessary adjustments.

• Admins: There is no admin control for this feature.
• End users: There is no end user setting for this feature. Visit the Help Center to learn more about transferring calendars or events in Google Calendar.

• Rapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on June 18, 2026

• Rapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on July 6, 2026

• Available to all Google Workspace customers

• Google Workspace Admin Help: Cancel or transfer events or secondary calendars before deleting a user
• Google Calendar Help: Transfer calendars or events in Google Calendar 
• Workspace Updates Blog: An update on secondary calendar lifecycle changes and a new API

1. Transfer API Endpoint

• How it works: This replicates the data transfer functionality available in the Admin console without requiring confirmation or email verification from the recipient.
• Requirements: Requires user authentication with the Manage Calendars administrator privilege and the useAdminAccess parameter set to true. [1, 2]

2. Organization Filter for Calendar Lists

• Usage: By combining this with the users.list method of the Admin SDK API, you can audit and retrieve a comprehensive list of organization-owned secondary calendars across multiple users.
• Ownership Check: The dataOwner field can be utilized to verify the current ownership status of a calendar. [1]

3. Dedicated Data Owner Rules [1]

• Deletion Rights: Only the designated data owner can delete a secondary calendar. Their access level cannot be downgraded from the default owner status as long as they own it. [1]
• Lifecycle Policies: With upcoming changes to how secondary calendars expire (such as auto-deleting when the owner’s account is deleted), these API updates ensure you can audit and reassign ownership of orphan secondary calendars before they are lost. [1, 2]