eSIMrateUICC (the chip that hosts eSIMs)
by RonyThe eUICC (embedded Universal Integrated Circuit Card) is the secure chip soldered into a phone, a watch or a tablet, able to download, store and run several carrier profiles. It is the hardware behind the eSIM: “eSIM” names the consumer experience, “eUICC” the chip and the technical standard that make it possible. Its unique identifier is the EID.
Why it matters when travelling
The eUICC is what makes the traveller's old ritual obsolete: no more paperclip, no more local card bought at the airport, no more home nano-SIM lost in a bag. The chip downloads a local profile in five minutes and can store several: your travel eSIMs from previous countries stay installed, ready to be switched back on.
Its remotely reprogrammable nature is also what allows profiles to be transferred, deleted and reissued with no physical handling: everything that makes the eSIM flexible follows from this chip.
The misconception
“eSIM and eUICC are two different technologies.”
They are the same thing seen from two angles: the eUICC is the chip (the hardware and its GSMA standard), the eSIM is the service it delivers (your dematerialised SIM card). When a spec sheet says “eUICC compatible”, it simply says “eSIM compatible” in engineer.
What it changes when you compare
When picking a plan, the eUICC differentiates nothing: every provider ships profiles to the same GSMA standard, compatible with every chip. Just remember the practical consequence: storage capacity varies between phones, so clear out expired profiles now and then.
Compare eSIM plans by destination
The rat's tip: Your eUICC stores several profiles, but a deleted profile is usually lost for good (prepaid eSIMs almost never reinstall). The right reflex: deactivate a profile rather than delete it, until you are certain you no longer need it.
See also
Frequently asked questions
How do I know whether my phone has a eUICC chip?
Dial *#06#: if a 32-digit EID appears, the chip is there and your phone supports eSIM. No EID, no eUICC: the model only takes physical cards, whatever its release date.
How many profiles can a eUICC store?
From 5 to around twenty depending on the phone, with one or two active at a time. You meet the limit fast if you travel a lot and never delete expired profiles: a yearly clean-up is enough.
What is the difference between eUICC and iSIM?
The eUICC is a dedicated chip soldered onto the board; the iSIM builds the same function straight into the main processor, with no separate component. The iSIM mostly equips IoT for now, while the eUICC remains the smartphone standard in 2026.