Suspending a subaccount blocks it from Twilio usage incurred from using the API, including phone calls, video, messages, and more. Twilio will not remove any phone numbers owned by this subaccount, and the parent account will continue to be charged for the numbers monthly. We leave it up to the owner of the project to determine if they want to release the phone numbers of the suspended subaccount, or if they want to implement a grace period.

For more information on subaccount suspensions, please see Suspending a Subaccount (Twilio Docs).

Alert: If you close a subaccount, Twilio will release all phone numbers assigned to it and shut it down completely. Closing a subaccount is an irreversible process; this is a permanent change. For more information, please see our article Closing a Twilio subaccount.