SIM Card Types and Sizes Explained

Choosing the wrong SIM for an IoT deployment can cost OEMs time, money, and long-term flexibility. A SIM that fits the device physically can still create problems if it limits carrier access, complicates activation, increases field service maintenance and truckrolls, or makes it harder to manage usage and billing at scale. This guide helps OEMs understand SIM card types and sizes and choose the right SIM strategy for their device, deployment plan, and business model behind the connected product.

SIM cards store the unique credentials devices need to authenticate with cellular networks and send or receive data. Originally designed for mobile phones, SIMs have evolved into multiple sizes, form factors, and technologies to support a much wider range of connected devices, from smartwatches and POS terminals to fleet cameras, industrial sensors, and heavy equipment.

While consumer SIMs and IoT SIMs perform the same basic function, IoT SIMs are designed for more complex operating environments. IoT deployments often involve large device fleets, varied data usage, different network requirements, longer device lifecycles, and business models built around recurring service revenue. Choosing the right SIM means evaluating more than physical size. OEMs also need to consider durability, carrier coverage, remote management, data plan flexibility, lifecycle control, and how connectivity costs will be tracked, managed, and monetized over time.

What is a SIM card?

A SIM card (Subscriber Identity Module) is a small chip that stores the unique credentials a device needs to identify itself and connect to a cellular network. SIM cards allow connected devices to authenticate with a carrier network, send and receive data, and maintain the information needed to support cellular service.

Traditional consumer SIM cards are most commonly associated with smartphones. These SIMs are typically tied to a single carrier, such as Verizon or AT&T, and support services like voice, text, and mobile data for an individual user. The carrier uses SIM-related service and usage information to associate that device with the correct account, plan, and billing structure.

For IoT devices, SIM requirements are more complex. A connected product may need to operate across multiple regions, support different data usage patterns, connect to different network types, remain active in the field for years, or be managed remotely at scale. Consumer SIMs are not usually designed for that level of flexibility, durability, lifecycle control, or business model support. IoT SIMs are built to help manufacturers and solution providers manage connectivity across fleets of devices, with greater visibility into usage, activation status, carrier access, and ongoing service costs.

What are IoT SIMs?

IoT SIMs, also known as Machine-to-Machine (M2M) SIMs, provide network access, store device and carrier information, and transfer data, just like consumer SIMs. However, IoT SIMs are capable of supporting IoT devices in a variety of connected applications, such as security cameras, fleet tracking, smart farming, and patient monitoring devices. Rather than one person needing one SIM card for one device, OEMs must manage thousands of devices with unique technology, data usage, and coverage requirements.

Additionally, IoT devices may require multiple carrier relationships, local native connectivity, or permanent roaming options. They also must be durable enough to survive in extreme conditions, highly mobile use cases, and reliably transmit data as they traverse global boundaries and geographies.

With the specific needs of IoT devices in mind, IoT SIMs must:

1. Have flexible data plans to support different levels of usage,
2. Be capable of mass activation,
3. Withstand harsh environments, temperatures, and vibrations,
4. Have a long lifespan (years longer than a traditional SIM),
5. Allow for remote management of devices deployed on a wide scale,
6. And support multiple carriers for extensive connectivity.

Learn more about the difference between IoT SIM cards and traditional SIM cards.

SIM card sizes

SIM cards are categorized by form factor (FF), which refers to the card’s physical size and shape. As cellular devices have become smaller and more specialized, SIM form factors have also evolved from the original credit card-sized Standard SIM to smaller Mini, Micro, Nano, and embedded options.

Form factors affect device design, durability, serviceability, manufacturing complexity, and long-term connectivity management. A removable SIM may make sense for larger devices that are easily accessible and require ongoing maintenance, while an embedded SIM may be better suited for compact, rugged, or sealed IoT devices that need to operate reliably in demanding environments or across global boundaries and multiple networks.

Some devices also use Tri-Cut SIM cards, which include 2FF, 3FF, and 4FF cutouts in a single card. This gives manufacturers and deployment teams more flexibility when supporting multiple device models or testing different hardware configurations.

The Evolution of SIM Form Factors

1. Standard SIM / 1FF

Size: 85.6 mm × 53.98 mm × 0.76 mm

The Standard SIM, also known as 1FF, was the original SIM card form factor. It was roughly the size of a credit card and was used in early mobile phones when device size was less constrained.

As mobile and internet-connected devices became more compact, manufacturers needed SIM cards that took up less internal space. As a result, the 1FF Standard SIM is now largely obsolete and is not used in modern IoT devices.

2. Mini-SIM / 2FF

Size: 25 mm × 15 mm × 0.76 mm

The Mini-SIM, or 2FF, is much smaller than the original Standard SIM, it is still large compared with newer Micro and Nano SIMs. In IoT, 2FF SIMs may still appear in larger equipment where internal space is less constrained and easy handling or replacement is useful. Examples include vending machines, ATMs, older vehicle systems, kiosks, and some industrial devices.

3. Micro-SIM / 3FF

Size: 15 mm × 12 mm × 0.76 mm

The Micro-SIM, or 3FF, reduced the physical footprint of the SIM card while maintaining a removable design. It became common in applications like smartphones, tablets, and GPS devices before Nano-SIMs became the dominant removable form factor for many compact devices.

For IoT deployments, Micro-SIMs can still be found in routers, gateways, tracking devices, and other mid-sized connected equipment. They offer a balance between smaller size and practical field serviceability.

4. Nano-SIM / 4FF

Size: 12.3 mm × 8.8 mm × 0.67 mm

The Nano-SIM, or 4FF, is the smallest removable SIM card format. It removes most of the surrounding plastic found in larger SIM cards, leaving a compact form factor that helps manufacturers preserve internal space.

Nano-SIMs are commonly used in smartphones, smartwatches, POS systems, compact routers, and other space-sensitive connected devices. For IoT manufacturers, the smaller size can help make room for batteries, sensors, antennas, processors, or other critical components. As devices become more streamlined and feature-rich, smaller SIM form factors have become more common across both consumer electronics and IoT products.

5. Embedded SIM / MFF2

Size: 6 mm × 5 mm × 0.9 mm

An embedded SIM, or MFF2 SIM, is a small chip that is soldered directly onto a device’s printed circuit board instead of being inserted into a removable SIM slot. They are ideal for IoT devices where space, durability, and security are important design priorities.

Because MFF2 SIMs do not require a removable tray or slot, they can help manufacturers reduce device size and simplify hardware design. They are also more resistant to vibration, moisture, dust, tampering, and physical damage, making them a strong fit for outdoor, mobile, industrial, and mission-critical IoT deployments. They can also facilitate multi-network connectivity by hosting multiple profiles that support diverse native connectivity options, networks, and global access.

Embedded SIMs are commonly used in devices such as fleet cameras, drones, asset trackers, industrial sensors, medical devices, smart meters, and other connected products that may remain in the field for years. For OEMs, this form factor can reduce the need for physical SIM access after deployment, especially when paired with the right connectivity management and provisioning strategy.

Why SIM size matters for IoT devices

The size and type of SIM card used by an IoT device should be influenced by its application, deployment, and projected lifecycle. A removable SIM requires a dedicated SIM slot, truck rolls, ongoing maintenance and replacements, and more internal space. A Nano-SIM offers a smaller removable option for compact devices that are frequently handled. An embedded MFF2 SIM facilitates lengthy service life for ruggedized or sealed devices, but it must be planned earlier in the manufacturing process because it is soldered directly into the device.

That is why IoT teams should evaluate SIM form factor alongside broader deployment needs, including:

1. Device size and internal component layout
2. Environmental exposure
3. Expected device lifespan
4. Need for field replacement or tamper resistance
5. Carrier and network requirements
6. Remote activation and lifecycle management
7. Data plan structure and billing model

Zipit helps OEMs think through these choices beyond the physical SIM card and price per gigabyte. With global cellular connectivity services, multi-carrier support, centralized connectivity management, and billing solutions custom-built for connected devices, Zipit helps teams choose an IoT SIM strategy that supports both the device design and the long-term business model behind the deployment.

Specific types of IoT SIM cards

There are various types of IoT SIM cards available, which are not necessarily interrelated, but you should consider all of them before making a decision on which SIM card to choose.

eSIMs

The term eSIM refers both to the embedded SIM form factor and the eUICC (Embedded Universal Circuit Card) software. The first describes a SIM soldered into a device, and the second is the software that enables remote provisioning and management of SIMs without requiring them to be swapped out. The software does not require a soldered SIM, comes in all form factors, and can be used for Consumer SIMs or M2M/IoT SIMs. When we discuss eSIMs, we’re referring to the eUICC software.

Every SIM card is equipped with a UICC (Universal Integrated Circuit Card) that makes it identifiable on the network, but in general, all SIM cards are associated with one network provider. This could limit the global coverage and roaming capabilities of a device if the single provider does not have roaming agreements with other carriers.

On the other hand, an eSIM/eUICC allows a SIM to switch providers and leverage different roaming agreements. For example, Zipit offers SIMs for IoT with more than one network profile for global coverage. One eUICC SIM card can connect to multiple networks over the air without requiring access to the device–this enables faster device deployment and rapid global scalability.

Learn more about what an eSIM is and if it’s right for your IoT device.

Multi-carrier & global SIM strategies

A multi-carrier SIM approach uses SIMs from multiple network operators in different regions. This differs from a global SIM, where the SIM card is capable of roaming by leveraging the roaming relationships of multiple carriers. Utilizing a multi-carrier SIM approach or multi-SKU approach can provide better coverage on a global scale. This strategy can leverage native connectivity and local networks owned by a SIM’s regional carrier rather than relying on roaming agreements between carriers. Often, this approach is more reliable and cost-effective than using a singular global SIM. They can also grant access to high data usage and battery-saving features like PSM/eDRX, which are often restricted for roaming devices.

The difficulty with using multiple SIMs comes with managing relationships and contracts with multiple carriers and efficiently managing SIM states or moving devices between plans. Certain carrier rate plans or very high data usage plans, like fixed wireless, are limited to a specific carrier offering those plans and do not allow for roaming. A 300GB plan would require multiple SIMs to offer the plan on multiple carriers. Carriers have specific restrictions with each other on how much data can be used while roaming on another network. These complications are mitigated by partnerships with a connectivity provider who can offer native connectivity and managed Tier 1 carrier relationships and contracts.

You can streamline multi-carrier SIM management with our IoT connectivity platform and partner with Zipit to manage your connectivity with the world’s top cellular carriers.

Steered vs. non-steered SIMs

Steered and non-steered SIMs behave differently when a device roams. No matter what alternative networks become available during roaming, a steered SIM will stay connected to the original carrier’s network or their preferred roaming list priority, even if the connection is weak. Non-steered SIMs, on the other hand, connect to the strongest available network by leveraging agreements between different carriers. Many IoT devices depend on non-steered SIMs for a continuous, stable connection.

When to use a physical SIM

Physical SIMs are still a practical choice for many IoT applications, especially when devices are easy to access or when teams want flexibility during testing, pilots, or early-stage deployments. A removable SIM can be swapped manually if a device needs a different carrier, plan, or troubleshooting path.

Physical SIMs can be a good fit for larger devices, routers, gateways, kiosks, vending machines, ATMs, and other equipment where a SIM slot does not create major space or durability concerns. They may also be useful when OEMs need a simple connectivity option before committing to a more integrated hardware design.

When to use an eSIM

eSIMs are often a better fit for IoT devices that need to scale, move across regions, or remain in the field for long periods without physical maintenance. With eUICC capabilities, an eSIM can support remote provisioning and profile management, allowing OEMs to update carrier profiles without physically replacing the SIM.

This is especially valuable for connected products like fleet cameras, asset trackers, drones, industrial sensors, medical devices, smart meters, and other devices that may be sealed, mobile, globally distributed, or expensive to service in person.

Which SIM strategy is the best fit for IoT deployments?

Neither option is automatically better for every deployment. A physical SIM may be the right choice for accessible devices, controlled environments, or early pilots. An eSIM may be the better choice for large-scale deployments where remote management, durability, and carrier flexibility matter more.

For OEMs, the best SIM strategy depends on the device’s size, environment, expected lifespan, data usage, carrier requirements, and business model. Zipit helps OEMs evaluate these tradeoffs and choose a SIM approach that supports reliable connectivity, centralized management, and scalable IoT monetization.’

Consumer SIM vs. IoT SIM: network technology differences

Consumer SIMs and IoT SIMs need to access a very different range of network technologies. Smartphones and tablets typically rely on mainstream consumer cellular networks such as LTE, 5G, and, as it becomes increasingly available, 5G RedCap. IoT devices, however, often have more varied connectivity requirements.

Depending on the use case, an IoT device may need to connect over LTE, 5G, 5G Redcap, LTE Cat 1 bis, LTE-M/Cat-M1, NB-IoT, or other cellular network technologies designed for specific device profiles. A high-data device like a router, camera, or digital sign may require LTE or 5G connectivity, whereas a battery-powered sensor, asset tracker, alarm panel, or smart meter may be better suited for low-power wide area network technologies (LPWANs) like LTE-M or NB-IoT.

Since IoT devices use such a wide range of cellular technologies, the SIM strategy must support the right network access for the device’s performance, power, and coverage requirements. A consumer SIM may be sufficient for IoT-specific network features. For OEMs, choosing an IoT SIM means confirming that the SIM, carrier relationships, rate plans, and connectivity management tools can support the network technologies their devices need in the markets where they will operate.

Learn more: LPWANs for IoT Connectivity: A Comprehensive Guide

How to choose an IoT SIM card

There are several different types and sizes of SIMs to choose from, and given the variability and complexities of IoT devices, the decision isn’t always straightforward. When choosing an IoT SIM card and provider, keep in mind the following.

1. Form factor: The size and design of the device determine the size of the SIM card and how much room it allows.

2. Native connectivity vs. roaming requirements: If your IoT device is moving across different countries or regions, you'll want to ensure that your SIM card provider has agreements with operators in those areas to avoid any disruptions in connectivity. You will need to choose between a single global SIM, a multi-carrier SIM approach or an eSIM strategy as the best solution.

3. Mobility and device location: If your device is deployed in a remote location, you’ll want to choose a SIM card that allows for remote provisioning. If your devices are highly mobile, you’ll want a SIM strategy that supports performance even as devices move across regions.

4. Network feature access: If your device needs to leverage power-saving network features like PSM/eDRX, you need a SIM solution that supports these premium features. This often means using a SIM strategy that lets you access authorized native connectivity.

5. Coverage and connectivity: The location of the IoT device may impact the strength of the signal and the available coverage options. It's important to choose a SIM card with a carrier that provides sufficient coverage in the area where the device will operate. If your devices are located worldwide, multi-carrier SIMs are often the choice we recommend.

6. Device environment: The SIM should be durable enough for the device’s operating environment. Devices exposed to vibration, moisture, dust, temperature swings, or outdoor conditions may benefit from an embedded SIM that is soldered directly to the device. Devices in controlled environments may be able to use removable SIMs without the same durability concerns.

7. Security and tamper resistance: Removable SIMs are easier to access and replace, but they can also be removed, stolen, or tampered with. For devices deployed in public, remote, or high-risk environments, an embedded SIM can reduce physical security risks and help protect the integrity of the device’s connectivity.

8. Management platform: Accessing data and managing the connectivity of IoT devices requires a secure management platform. Zipit can provide you with the best IoT SIMs for your devices from top carriers, along with a single platform to manage and monetize your devices.

9. Data usage and rate plans: A low-power sensor may use only small amounts of data, while a fixed wireless router, video device, or fleet camera may require a high-data plan. Your SIM provider should offer flexible data plans that align with real usage patterns, deployment regions, and customer pricing models.

10. Monetization and billing: For many OEMs, connectivity is part of the customer-facing service model. If your business sells subscriptions, bundled service plans, usage-based pricing, or premium connectivity tiers, your SIM strategy should support accurate usage tracking and billing. Zipit helps OEMs connect SIM management with subscription and usage-based billing, making it easier to monetize connected devices as they scale.

11. Provider expertise: The best IoT SIM strategy depends on more than the card itself. It requires the right mix of carrier relationships, coverage planning, data plans, platform tools, and billing support. Zipit helps OEMs choose IoT SIMs from top carriers, manage connectivity through a centralized platform, and build recurring revenue models around connected devices.
    

Unlock global growth with Zipit Wireless’s SIM strategies

Choosing the right SIM strategy is only one part of building a scalable IoT deployment. OEMs also need to determine how devices will be activated, which carriers and rate plans should support each use case, how SIM states will be managed over time, and how connectivity usage will be tracked, billed, and monetized. Without the right partner, those decisions can quickly turn into multiple carrier contracts, disconnected platforms, manual workflows, and unnecessary operational complexity.

Zipit Wireless helps OEMs simplify the full connectivity lifecycle. With more than a decade of experience supporting connected device businesses, Zipit helps teams evaluate SIM options, design carrier strategies, manage device connectivity, and support recurring revenue models. Instead of negotiating and managing separate relationships with multiple carriers, OEMs can work with Zipit to access reliable cellular connectivity across major markets through a single managed partner, regardless of your SIM strategy.

How Zipit helps OEMs manage IoT SIM deployments

• Managed multi-carrier connectivity: Access coverage across major markets through Zipit’s network of Tier 1 carrier relationships.
• Simplified carrier management: Reduce the burden of negotiating, integrating, and managing multiple carrier contracts on your own.
• Flexible data plans: Match connectivity plans to different device types, usage patterns, deployment regions, and customer needs.
• Centralized connectivity management: Use a branded device management platform to view active SIMs, monitor carrier connections, change SIM states, and move devices between data plans.
• Support for global deployments: Build a SIM and connectivity strategy that can support devices across regions without adding unnecessary operational overhead.
• Built-in monetization support: Connect data usage, subscriptions, and customer billing through Zipit’s billing platform, making it easier to package connectivity into recurring revenue offerings.

With Zipit, OEMs can move beyond simply choosing a SIM card. They can build a connectivity strategy that supports device performance, operational control, customer billing, and long-term global growth.

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