For device manufacturers one of the main advantages of an embedded SIM is that it requires much less space than the slot required for a removable SIM, even when it is a nano-SIM (4FF). But just how big are eSIMs that are soldered on the circuit board? Many pictures on the web seem to be inaccurate to the extreme…
Here are a few resources that give some details on that:
The first is a recent post on Anandtec that shows a number of pictures of removable SIM card form factors everybody knows, the standard eSIM form factor (MFF2) and even smaller, but so far non-standardized, sizes. While reading their post I was wondering if the standardized MFF2 form factor is only used in M2M devices or also in consumer products. A bit down in their post it is stated that they have taken a look inside a Samsung smartwatch and found an embedded SIM of that form factor inside.
On this page, Gemalto gives the exact dimensions of ETSI standardized embedded-SIMs: 5 mm x 6 mm. That is a bit more than half the size of the current 4FF removable nano-SIMs (12.3 x 8.8 mm). I’ve found other resources that show pictures of 4FF and and MFF2 embedded-SIMs side by side. Many of them, however, don’t seem to be accurate at all, the eUICC is always shown to be much smaller than the removable nano-SIM.
P.S.: The Anandtec article wrongly states that the first SIM cards were introduced in 1991 with GSM. That is not correct, in fact the C-Netz (the GSM predecessor network in Germany) already had SIM cards dating back to 1988, have a look here.