What is iSIM
Quick definition
iSIM (integrated SIM) is a SIM whose silicon lives inside the modem or SoC, not as a separate chip. It shares the same eUICC logic and the same GSMA standards, but takes zero extra board space and trims bill of materials.
Difference from MFF2 and eUICC
MFF2 is a separate solderable chip. eUICC describes profile programmability. iSIM collapses the chip into the modem SoC. iSIM can (and usually does) carry eUICC; only the physical integration changes.
When to pick iSIM
Very high volumes (>100k units) where removing a component cuts BOM and boosts ruggedness. Also in wearables and devices where millimeters matter.
FAQ
Which SoCs integrate iSIM today?+
Quectel BG770A, Sequans Monarch 2, Nordic nRF9151, and others released between 2023 and 2025. The offering is growing fast.
Does iSIM change the provisioning model?+
No, still SGP.32 or SGP.22. Only the physical layout differs: one chip fewer, same OTA provisioning flow.
Related terms
What is eUICC
An eUICC (embedded Universal Integrated Circuit Card) is a programmable SIM chip that can hold several carrier profiles and switch between them over the air. It is the GSMA standard underpinning every modern eSIM, in phones, vehicles, and IoT devices.
What is MFF2
MFF2 (Machine-to-Machine Form Factor 2) is the solderable SIM: a 6x5 mm chip mounted directly on the PCB, no tray or socket. It is the de-facto standard in industrial IoT, automotive, and any device facing vibration, humidity, or extreme temperatures.
What is IoT eSIM
IoT eSIM is the eUICC SIM designed for headless devices. It inherits smartphone eSIM programmability but uses a Pull provisioning flow (SGP.32) where the device asks the server for a profile, without scanning a QR code or entering an activation code.