We’re introducing two enhancements to the Calendar API that make it easier for admins to programmatically manage secondary calendars within their organization: a transfer API and a filter for secondary calendars owned by your organization.Transfer APIAs 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.Organization filterTo 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.Getting startedAdmins: 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.Rollout paceTransfer APIRapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on June 18, 2026Organization filterRapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on July 6, 2026AvailabilityAvailable to all Google Workspace customersResourcesGoogle Workspace Admin Help: Cancel or transfer events or secondary calendars before deleting a userGoogle Calendar Help: Transfer calendars or events in Google Calendar Workspace Updates Blog: An update on secondary calendar lifecycle changes and a new API