eUICC is often mistakenly associated with eSIMs.

eUICC (Embedded Universal Integrated Circuit Card) is the software component of a MIS. As such, it is not a physical object.

eUICC is a functionality that allows you to remotely store multiple Mobile Network Operator (MNO) profiles and switch between them using Over-The-Air (OTA) technology.

In other words, thanks to the eUICC functionality, you can have multiple numbers with only one SIM and easily switch between them by changing the settings.

A SIM card with UICC functionality can only install and use a number.

However, while the eUICC is designed to support multiple MNO profiles on the same device, they can only be used once.

It would be best to remember that not all eSIMs have eUICC, and some classic SIM cards may now have this functionality.