To check if a phone is compatible with T-Mobile's network, visit T-Mobile.com, and select "Bring Your Own Phone" under the "Shop" menu. Select your current phone from the list or use the serial number checker to find out whether the device can be registered with T-Mobile.
As of 2015, T-Mobile supports GSM devices from manufacturers including Apple, Samsung, LG, Alcatel and Motorola. Phones listed as being compatible with the Bring Your Own Phone program include the Apple iPhone 6, Samsung Galaxy S5, LG G Flex, Google Nexus 5 and HTC One M8. If a device is not listed, search for it using the search box below the list of supported phones. Alternatively, access the serial number checker by clicking the link text underneath the search box. To use the serial number checker for an unlisted device, locate the 15-digit IMEI number of your phone under the battery, and enter it without hyphens when prompted.
T-Mobile provides starter kits for customers using the Bring Your Own Phone program that include either a nano, micro or standard SIM card. Once you insert the SIM card into your device, you must activate it at a T-Mobile store, through T-Mobile.com or by calling T-Mobile's customer support line.