eSIM
Embedded SIM
An alternative to physical, removable SIM cards that instead embeds SIM functionality into the phone hardware.
See: SIM
Instead of swapping physical cards to associate a phone with a different account (and phone number), the change is made in software over the network.
eSIM uses far less physical space inside a phone than a SIM card slot, and enables cellular functionality in devices too small to accommodate physical SIM cards, such as smartwatches.
