IoT SIMs That Scale With You

IoT SIMs for Devices That Need to Stay Online

An IoT SIM is a SIM built for devices that run unattended, such as routers, meters, cameras, chargers and trackers, rather than for phones. Millbeck supplies IoT SIMs for UK and international deployments: unsteered UK roaming SIMs, global roaming SIMs, eSIMs and eUICC SIMs, with security options and one platform to manage them.

We have supplied IoT connectivity and cellular hardware since 2008, so we supply the routers and antennas as well as the SIM. You speak directly to our team in Leeds, who can tell you which SIM suits your devices, your sites and your budget.

How Is an IoT SIM Different From a Phone SIM?

An IoT SIM differs from a phone SIM in how it connects, how it is managed and how it is billed. A phone SIM is built for one person with one handset on one network. An IoT SIM is built for many devices, often in places nobody visits, running for years.

• Networks: a Millbeck IoT SIM can connect to more than one network, so one operator's weak coverage or outage does not take a device offline.
• Management: you activate, suspend and retire SIMs from one platform, rather than managing each one separately.
• Security: private APN, fixed IP and VPN options keep device traffic off the public internet.
• Billing: pooled data and per GB tariffs suit devices whose data use varies, rather than a fixed monthly bundle per SIM.

The SIM is a small part of a deployment's cost, but it decides whether a device stays online. Changing SIM type after installation usually means a site visit to every device, so it pays to choose before you deploy.

Which IoT SIM Do I Need?

The right IoT SIM depends on where your devices are, whether they move between countries, and how long they will stay in service. Millbeck offers four types of IoT SIM.

UK Roaming IoT SIMs

A UK roaming IoT SIM connects to more than one UK mobile network, so a device can move to another network when the one it is using fails. Millbeck UK roaming SIMs are unsteered across EE, O2, Vodafone and Three, and support VoLTE for devices that make voice calls. Most of our customers deploy only in the UK, and this is the SIM that suits them. See UK Roaming SIMs.

Global Roaming IoT SIMs

A global roaming IoT SIM connects to mobile networks in many countries on one SIM. Millbeck global roaming SIMs have unsteered access to more than 600 networks in over 180 countries, with fixed IP options for secure remote access. They suit fleet telematics, OEMs shipping into several markets and infrastructure spread across countries. See Global Roaming SIMs.

IoT eSIMs

An eSIM is a SIM chip soldered onto a device's circuit board rather than a removable card. The usual form for IoT devices is MFF2, a small chip designed for industrial conditions. An eSIM cannot be removed and used elsewhere, stands up better to vibration and temperature than a card in a slot, and takes SIM handling off the production line. See IoT eSIMs.

eUICC IoT SIMs

eUICC (Embedded Universal Integrated Circuit Card) is SIM technology that holds several operator profiles and lets you switch between them remotely. An eUICC SIM can be a removable card or a soldered eSIM. eUICC lets you change network over the air, without an engineer visit, which matters for devices expected to run for 10 years or more. eUICC is standard for our global deployments.

Security Options for IoT SIMs

Millbeck IoT SIMs support private APN, fixed IP, IPsec VPN, IMEI lock, and SMS and voice barring, so you can match security to each deployment.

• Private APN: an APN (Access Point Name) is the gateway a SIM uses to reach a network. A private APN keeps your devices' traffic off the public internet.
• Fixed IP: a permanent private or public IP address for each SIM, so your systems can always find the device. Fixed IP is optional, and we include it whenever a VPN is specified.
• IPsec VPN: an encrypted link from our core network to yours, so traffic travels between your devices and your systems without crossing the public internet.
• IMEI lock: stops a SIM working in any device other than the one it is assigned to.
• SMS and voice barring: removes services a device does not need, so they cannot be misused or run up unexpected charges.

Our IoT SIM Security page explains when to use each option.

Managing IoT SIMs and Data Plans

Our SIM management platform lets you control every Millbeck IoT SIM from one place. You can activate, suspend or retire SIMs as devices go into and out of service, apply group policies, and suspend a SIM automatically when its usage passes a threshold you set.

We offer pooled data plans, where a group of SIMs shares one data allowance, and per GB tariffs, where you pay for the data each SIM uses. Our API lets you build SIM management into your own systems. You get every network under one agreement with us, rather than a contract with each operator.

Choosing IoT SIMs for Long-Life Deployments

An IoT SIM for a long-life deployment needs to keep working as networks and operators change around it. EV chargers, building controls, meters and telemetry often stay in service for 10 years or more.

• Network switch-offs: all four UK operators have switched off 3G, and 2G will close by 2033. Devices that depend on 2G need a plan now. Our article What Is VoLTE? covers voice devices.
• Operator changes: operators merge and change their agreements. Vodafone and Three merged in 2025, for example. A SIM that can use several networks is less exposed to any one operator's decisions.
• Changing requirements: data use tends to grow over a deployment's life. Pooled data and per GB tariffs let the plan change without changing the SIM.

For devices that are hard to reach or deployed in large numbers, eUICC lets you change network profile remotely, which can avoid a SIM swap programme years into the deployment.

Frequently Asked Questions

What Is an IoT SIM?

An IoT SIM is a SIM designed for connected devices that run unattended, such as routers, sensors, meters and trackers. Compared with a phone SIM, an IoT SIM usually offers access to more than one network, central management from one platform, private networking options and data plans shared across many devices. Millbeck supplies UK roaming, global roaming, eSIM and eUICC IoT SIMs.

Is an M2M SIM the Same as an IoT SIM?

An M2M SIM and an IoT SIM are the same product under two names. M2M (machine to machine) is the older term, used before IoT (Internet of Things) became common. Both describe a SIM built for devices rather than phones. Millbeck has supplied M2M and IoT connectivity since 2008 and uses the term IoT SIM today.

Can I Use a Phone SIM in an IoT Device?

A phone SIM will often work in an IoT device, but it is rarely the right choice for a deployment. A phone SIM connects to one network, cannot be managed centrally, and has no private APN or fixed IP options. For a deployment, an IoT SIM gives you the network choice, control and security that a phone SIM does not.

What Is the Difference Between eSIM and eUICC?

eSIM describes the physical form: a SIM chip soldered onto the device instead of a removable card. eUICC describes a capability: holding several operator profiles and switching between them remotely. A SIM can be an eSIM, eUICC, both or neither. The terms are often used interchangeably, so check which one a supplier means before you specify.

How Are IoT SIMs Billed?

Millbeck bills IoT SIMs on pooled data plans or per GB tariffs. A pooled plan gives a group of SIMs one shared data allowance, so devices that use more data one month are balanced by devices that use less. A per GB tariff charges for the data each SIM uses. Our team will recommend the model that suits your devices.

Does Millbeck Supply Routers and Antennas With IoT SIMs?

Millbeck supplies cellular routers and antennas alongside our IoT SIMs, so you can buy a working deployment from one supplier. We are a Teltonika Diamond distributor and also supply Proroute, Robustel, Milesight and Ericsson Cradlepoint routers. When we supply the router, we configure it to your specification, load the latest firmware, and check it connects before dispatch.