Context: Over the years, the size of the SIM card has shrunk from SIM to mini SIM to micro SIM to nano SIM. The latest is the eSIM with specifications defined by the Global System for Mobile Communications (GSM) Association.
What is a SIM?
‘SIM’ stands for ‘subscriber identification module’. It is an integrated circuit, or a microchip, that identifies the subscriber on a given network.

What is an eSIM?
- An eSIM is an embedded SIM, where the SIM software is loaded on to a Universal Integrated Circuit Card (UICC), that is permanently embedded as part of the motherboard of a smartphone/watch. Being attached to the motherboard, eSIMs allow re-programming, letting users switch operators without having to replace any physical SIM cards.
- An eSIM has two immediate advantages.
- It is environmentally friendlier than a physical SIM, as it is reprogrammable i.e., there is no need for more plastic and metal for a new SIM.
- If a malicious person gains access to the phone, they will not be able to separately access the SIM application nor be able to duplicate it.
- The disadvantage is that an eSIM can, in theory, allow network operators to track subscribers’ data, including inside Apps on the device, especially in the absence of data privacy laws.