T-MOBILE Sim Identity Module Guide

SIM stands for Subscriber Identity Module. The SIM card is a tiny chip that’s inserted into your phone. It’s tied to your phone number and identifies you, the subscriber, to the T-Mobile network. It can also store data like phone numbers and contact info. The T-Mobile SIM card contains three difference SIM sizes: standard, micro, and nano.

Some phones and devices have an eSIM (embedded SIM card) built right in, so there’s no need to install a SIM card. An eSIM is part of the device and can’t be removed. Some devices even offer dual SIM capability—one eSIM and one removable SIM—so you can have two phone numbers on one device (for example, a work number and a personal number).