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If you want to use your smartphone, you’ll need a SIM card of some sort. The Subscriber Identification Module (SIM) assigns you a phone number and connects your phone to a mobile network or carrier. Without a SIM, you can’t call, text, or use any of the best data plans.
In recent years, the physical SIM card has been overshadowed by the eSIM, culminating in Apple’s decision to remove physical SIM card slots from the iPhone 14 lineup. And while less well known, iSIM has the potential to eclipse both of these. We explain what each SIM card does and outline their differences.
What is a SIM?
A SIM card is a physical card you slot into your phone. It was developed in 1991 and has shrunk over the years from the Mini-SIM to Micro-SIM and finally to Nano-SIM, which is now the industry standard for these physical chips. They slot into your phone normally in a tray that pops out the side of the phone.
A SIM card’s most significant benefit is its portability. You can switch between devices in seconds, and you won’t have to contact your carrier. The downside is that the tray takes up space inside a smartphone. Given the amount of tech packed into the sleek chassis of modern smartphones and the race to create the biggest and best cameras, every millimeter of extra space is valuable.
SIM cards are also often locked to a single network and require carrier intervention to make any changes that you may want to make. An eSIM, on the other hand, can be activated and deactivated on the phone, usually without any carrier intervention.
What is an eSIM?
An eSIM is an embedded SIM card fitted into the phone’s motherboard. It runs on the same networks as standard SIM cards, so there’s not much difference in how they work outside the initial set-up and transferring of your number and plan.
The main benefit is the size reduction. While the Nano-SIM may seem minuscule and tricky to slot into your smartphone, eSIMs are smaller. Three times smaller. This opens up more room inside your phone for features like a larger camera module or a bigger battery, and it also removes one of the openings for water and dust.
If you have an eSIM, you can often use it in conjunction with your physical SIM, allowing you to have both your personal and work numbers tied to a single device. You can also slot in a foreign SIM card if you’re traveling abroad and want to save money on those stinging data costs. Many smartphones now allow an eSIM to be used for your mobile data, adding to their convenience factor when traveling to foreign countries. You can retain your phone number for regular communication.
Setting up an eSIM is an entirely different process from a SIM card. The process differs between carriers and devices, so you’ll want to carefully follow the instructions for setting up an eSIM.
Not all phones are compatible with eSIMs, though most modern flagships have added support in recent years. Most of the best Android phones support eSIM, and iPhones are now eSIM exclusive. If you’re unsure, check the handset’s technical specifications before adding an eSIM to your basket. It’s also worth checking that your carrier supports the eSIM service, especially if it’s a prepaid plan. Despite being more affordable than a regular phone plan, these plans are usually hosted by MVNOs, which may not support eSIMs.
What is an iSIM?
The iSIM is the latest innovation in SIM card technology, embedding the chip into your phone’s inner workings even further and reducing the size even more. Developed by ARM, the iSIM has primarily been developed with Internet of Things (IoT) devices in mind.
iSIMs have been developed following the need for smaller, cheaper, and more secure SIM cards. And they do just that. Thanks to their incorporation in the cellular module, they come in at 98% smaller than an eSIM and are 50% cheaper to make due to fewer components and simplified designs streamlining the manufacturing process. They also use up to 70% less power, meaning your future phone’s battery could last longer.
They’re not all sunshine and rainbows, though. As iSIMs are a new technology, they’ve yet to be adopted by major smartphone manufacturers. This is less an issue for consumers and more for manufacturers of iSIMs to overcome to relieve bottlenecks in production and manufacturing.
The main benefit is security. They are physically and logically more secure than eSIMs. Integrating into the SoC (on a secure enclave, no less) of your smartphone means it cannot be physically accessed and provides a root of trust for the mobile network with an additional layer of authentication to access.
As iSIMs are still a relatively new technology, compatible devices and carriers are few and far between. Qualcomm’s Snapdragon 8 Gen 1, released in 2021, was the first SoC confirmed to support iSIM technology and most of the best Android phones. However, you’ll still use eSIMs with these phones, and we expect it’ll be some time before iSIMs cause as much of a ruckus as eSIMs.
Have you switched to an eSIM?
And just like that, you now know the difference between SIM, eSIM, and iSIM. Are you still using a traditional SIM, or have you transitioned to eSIM?
Maybe you’re the proud owner of a new Google Pixel 7 or Pixel 7 Pro. In this case, you can have two eSIMs on your phone, a step forward from one physical and one digital. Of course, you can still use your physical SIM without any issues.
