Locate a T-Mobile phone by subscribing to T-Mobile's Lookout Mobile Security Premium service through the Lookout website. A Google map displays the location of the phone and the service sends an email that shares the location with the account holder.
The service has a scream function that causes the phone to sound a loud siren, vibrate and flash, so the phone becomes locatable. The service also features signal flare, which saves the phone's last known location when the battery is running low. The Lookout app is available through Google Play and the Apple App store. However, T-Mobile loads the app onto most phones before selling them.