Delete a Closed Track in Google Play Console

Deactivate track is available for any custom track created by user. Remove testers is applicable for any play console provided track.

It isn't exactly possible right now.

However, you can:

• click on the 'Manage' button
• expand the 'Managed testers' card
• click on the 'Deactivate track' button.

The track will go in a 'Deactivated tracks' list in the 'App Releases' page."

It's not totally deleted, but that might be enough for you. I've sent the feedback to the right team that this wasn't completely discoverable, and that complete deletion for unused tracks would be useful.

You also can't delete the default "Alpha" or "Beta" tracks right now, only ones you have created yourself.