Hey there, that's a really good question! This is the Bluetooth version of this watch. 4G LTE standalone connectivity is only available on the Samsung Galaxy Watch LTE version. Standalone voice calling on the LTE version requires initial pairing with eligible Samsung Galaxy device and a separate qualifying wireless plan. Your carrier may not support standalone voice calling, or support may be available only in certain areas. Please check with your carrier for more information. Standalone functionality is limited if the paired phone is not powered on or connected to a wireless network. ^Elizabeth