Hi, @Sandy4OU Domestic SIM Unlock (DSU) refers to enabling the SIM slot of your device to allow you to insert another carrier's SIM card. SIM unlocking a device will not necessarily make a device interoperable with another carrier's network. Additionally, SIM unlocking a device may enable some functionality of the device but not all (e.g., a SIM unlocked device may support voice services but not data services when activated on a different network). NOTE: Not all devices are capable of having the SIM slot unlocked. You can learn more about it at https://www.boostmobile.com/#!/about/legal/ctia-regulatory/ If anything else, we're here to help.