T-Mobile recently disabled self-service SIM changes as it made some adjustments to the process. This was Un-carrier’s way to help strengthen the security of such requests and protect its customers. And now, a report shows that T-Mobile has implemented the new security changes and is ready to roll them out to customers.
While this new SIM protection feature is meant to protect its customers’ accounts, the Un-carrier is not yet ready to re-enable the self-service SIM change option. But you can already add protection to your SIM card at the individual line and account level. By doing this, you can prevent any changes to the SIM card until you remove the lock.
You can activate SIM card protection through the T-Mobile website, app, call support, or by visiting a T-Mobile store.
Source: The T-Mo report