Just checking to see if there has been any update or progress on this, we are wanting to add our customer portal users to sso and we can't?
Thank you for reaching out to Atlassian Community!
Checking the feature request, the last update was in October 2019 informing that there is no ETA for the feature to be implemented.
The only workaround at the moment is to migrate customers to Atlassian account, so instead of logging in on the customer portal, they will go to xxxxx.atlassian.net to login using SSO and then, as they won't have a Service Desk license, they will be redirected to the customer portal.
It will be necessary to migrate them one by one since the option to bulk migrate is not available at the moment:
Please, click on vote and watch in the features to receive future updates.