The form factor argument is the wrong argument. Teams spend weeks debating removable SIM against eSIM against iSIM, decide on the smallest footprint, and then discover in month seven that the devices shipped to Turkey have been disconnected for permanent roaming and there is no way to change the profile without sending an engineer.
The hardware question has a straightforward answer. The one that decides whether a global deployment survives contact with regulators is different: where does the device end up, whose network does it land on, and who changes that after the box is sealed?
Removable SIM is the plastic card, in 2FF, 3FF, or 4FF. One profile, physically swappable, replaceable by a person with hands on the device.
eSIM is a chip soldered to the board, in MFF2 form. It holds multiple carrier profiles and accepts new ones over the air under GSMA remote provisioning specifications. The physical part is permanent. The network relationship is not.
iSIM puts the same function inside the device's system-on-chip, with no separate component at all. Same remote provisioning model, smaller footprint, lower power draw, one fewer part to source.
All three carry an IMSI. All three identify the device to a network. The difference is who reaches the profile once the device is in the field.
| Capability | Removable SIM | eSIM (MFF2) | iSIM |
|---|---|---|---|
| Profile change after deployment | Site visit | Over the air | Over the air |
| Multiple carrier profiles | One at a time | Several stored | Several stored |
| Physical failure points | Socket, corrosion, vibration | Soldered | None separate |
| Board space and power | Highest | Low | Lowest |
| Hardware support in 2026 | Universal | Wide | Limited to chipsets that carry it |
| Response to a roaming restriction | Replace the card | Push a local profile | Push a local profile |
| Field logistics at 5,000 units | Engineer per device | None | None |
A device that sits on a foreign network indefinitely is doing something the roaming system was not designed for. Regulators in Turkey, Brazil, India, and Saudi Arabia restrict it. Some enforce with a 90-day window, some with outright refusal to attach. Carriers enforce their own limits on top.
The consequence lands months after deployment, on devices already installed on somebody's wall. With a removable SIM in 5,000 units across nine countries, the fix is 5,000 site visits. With remote provisioning, it is a profile push. IXT supports local IMSI options in key markets to reduce permanent roaming risk, which is the same problem addressed one layer up.
Data residency rules and national licensing decide which carrier a device is allowed to use, and those rules move. A form factor that locks the carrier relationship at manufacture locks you to the rules as they stood at manufacture.
The GSMA specification written for IoT removes the assumption that a person is present to approve a profile change. Earlier consumer specifications assumed a phone screen and a user. SGP.32 assumes a meter on a pole. For fleets provisioned in bulk, that distinction decides whether remote provisioning works in production or only in the datasheet.
Vibration, humidity, and temperature cycling attack SIM sockets. In vehicles, vessels, and outdoor cabinets, the socket fails before the modem does. Soldered eSIM and integrated iSIM remove that failure mode. This is a reliability argument rather than a connectivity one, and it decides more maritime and automotive deployments than roaming does.
Choose a removable SIM for pilots, for single-country deployments, for hardware already in production without an eSIM footprint, and where devices are reachable by a person without a truck roll.
Choose eSIM for multi-country fleets on hardware you control, for outdoor or mobile deployments, and anywhere a roaming restriction would otherwise mean a site visit. For most cross-border deployments in 2026, this is the default.
Choose iSIM when the chipset supports it and board space or power budget is under pressure, in high-volume products where removing a component matters at scale.
Worth stating plainly, because eSIM gets sold as an answer to problems it does not touch.
eSIM gives you the mechanism to change a profile. It does not give you the carrier agreements to change it to. Remote provisioning against a single carrier relationship is a mechanism with nowhere to go. What matters underneath is the number of networks reachable and who negotiated them: one IXT SIM covers 600+ mobile networks across 190+ countries, and IXT holds those carrier relationships rather than passing them through.
The form factor also does nothing for security. Identity, private routing, segmentation, and per-session enforcement are separate layers. A soldered chip is no more defended than a plastic card.
For new multi-country hardware, yes, at pace. Removable SIM holds its place in pilots, in retrofits, and on hardware already through certification.
No. It gives you a route out of one: a local profile pushed to the device instead of an engineer sent to it. Without local profiles available in that market, the mechanism has nothing to load.
On chipsets that carry it. Availability is the constraint rather than maturity, so confirm support with your module vendor before committing a design.
Yes, under GSMA remote provisioning, and SGP.32 is the specification to ask about for IoT fleets. Confirm the platform supports bulk operations, because provisioning 4,000 devices one at a time is a different task from provisioning one.
At unit level, removable SIM. Across a five-year deployment, the site visits triggered by a single roaming restriction cost more than the hardware difference across the whole fleet.
If a regulator in one of your markets restricted permanent roaming next quarter, what would it take to keep those devices online?
Answer that, and the form factor decision has already been made. Ask us how it works for your deployment.