Wireless Service

How Does an eSIM Card Work?

Kyle Reyes
April 24, 2023

Embedded sims are an awesome new technology that you may have noticed in your phone or in the store of your wireless provider. Many phones can use an eSIM phone plan as your primary account instead of your regular one, but it leaves many people wondering — how does an eSIM card work? We’re here to answer that question. This article will cover what eSIM cards are, a brief history of their development and usage, and how they are used in various industries. 

What is an eSIM Card?

This section will cover eSIM cards. The basic idea behind eSIM cards is simple. They are SIM cards embedded into the hardware of the phone that do all the things that physical SIM cards do, but they do it digitally. 

The SIM card connects your device to your carrier’s network, letting it transfer data on that network. Without an active SIM card, a smartphone has the same functionality (in general) as a tablet or a laptop. On a WiFi network, it has full internet access, but it lacks the mobile connectivity that turns it into a smartphone. That mobile connectivity is your calling, texting, and mobile internet. You can swap your SIM card (physical or embedded) from phone to phone with little issue, which means you can retain your phone number and contacts when you move to a new phone. 

Over the years, you likely came into contact with SIM cards as you switched phones or providers but did not spend too much time thinking about them. They hold a lot of important information for your number and account, but as long as everything is going smoothly, you should not have to think about your SIM card too much. 

How Does an eSIM Card Work in Your Smartphone? 

Your eSIM card functions in the background, holding all your device’s information inside and keeping your account settings connected to your mobile network provider. It functions just like a physical SIM card, whose major function is ensuring that your phone is always connected to your mobile network. While the hardware of your phone’s SIM card has changed over the years, the functionality remains the same. The eSIM card ties your phone into the network and lets your carrier know that your phone has the right to broadcast. It does that exceptionally well. 

You would most certainly notice if your SIM card were acting up. Fortunately, that is rarely an issue. Embedded SIM cards function just as well as physical SIM cards, and, since they are ensconced safely inside your phone, you don’t have to worry about them coming to any harm during normal phone operation.  

SIM cards come in various sizes, with eSIM cards being the smallest of all. That decreased size, and the lack of need for a SIM slot lets devices get smaller and sleeker. Image courtesy of PCmag

Other Applications for eSIM Cards

While our focus on eSIM cards generally rests in their application in mobile phones, we would be remiss not to touch on their other amazing applications. Their applications in Internet of Things (IoT) devices go much further than their changes to mobile phone applications. The biggest change with eSIM cards is this; embedded SIM cards are reprogrammable through remote software updates. Physical SIM cards are not reprogrammable while they are on a device. Switching your phone’s physical SIM card is a piece of cake, but swapping out physical SIMs when there are thousands or tens of thousands of devices on campus or in a warehouse is, shall we say, logistically challenging. 

The new possibilities of eSIM cards were not lost on tech manufacturers around the globe. We want to touch on two big applications of eSIM cards in the United States and the world. These technologies remain in development, but many companies and organizations utilize eSIM devices daily. 

Devices on the Internet of Things

The Internet of Things describes all small objects connected to the Internet. Objects like traffic lights, watches, appliances, security systems, and all “smart” technology are devices on the Internet of Things. Lots of these devices are small, or are optimized to be as small as possible. An eSIM card instead of a physical SIM card allows those devices to stay tiny and easier to manufacture. The gradual decrease in SIM card sizes lets manufacturers optimize their devices more and more, utilizing space for other key electronics. Alongside the decreased size, the eSIM is soldered into the device, nixing any need for a SIM card slot that’s reachable from the outside of the device. Integrating eSIMs into smart devices instead of physical SIMs opened many doors for product designers to find better models for their electronic devices. 

Perhaps the most significant change, however, is the ability to reprogram the SIM cards of devices with eSIMs remotely. This marks a huge difference for IoT device functionality and opens up a much more flexible workflow. Whenever a device requires a software update or a change to its mobile network, that change can originate from the main building rather than at each device individually. 

Industry and Manufacturing

This ability for remote change means eSIM management can happen in bulk. Manufacturing plants with thousands of machines in their warehouses can send a blanket order to all their devices with the push of a button. The use of eSIMs also assists companies that provide mobile service plans to their employees. If thousands of employees use company phones and the company decides to change providers, all of those changes can happen simultaneously rather than waiting on the bulk shipment of physical SIMs. Overall, corporate management of cell phone plans is made much easier with integrating eSIM cards and cell phone plans. 

IoT devices provide great boons to manufacturers interested in increased remote control over the software in their devices. In many industries, connecting more and more devices to a central network provides great benefits for the company and the employees. Smart devices have the potential to increase efficiency and automate various processes throughout a company. While eSIMs are popular in industries, major wireless providers have not always been keen on adopting eSIMs over physical SIM cards. Embedded SIM cards have many advantages over physical SIMs in small, numerous machines, but the differences in a smartphone specifically are much less noticeable. Still, US wireless providers all provide eSIM compatibility. 

There is a lot of care put into the creation and optimization of eSIM cards, and now those cards can perform fantastically in many industrial and commercial settings. 

Physical SIMs and eSIMs in Cell Phones

With the option open, it is no surprise if you are considering changing your phone to the new and shiny eSIM function with your new plan. 

If you’ve just purchased a new device or are planning to switch to a new carrier, you’ve likely run into the option of using an eSIM card on your new account. The good news is that a particular decision has little overall effect on your phone usage, but it is still good to decide confidently! If you wonder what that means, you are in the right place. This section will cover the differences in your phone’s functionality with an eSIM versus a physical SIM and how to switch from a physical SIM to an eSIM and vice versa. 

Physical SIM versus eSIM in a Smartphone

A few differences exist in phone usage when using a physical SIM versus an eSIM. Both cards function similarly, connecting you to the network equally efficiently. The differences are mainly in convenience and comfort. Switching carriers is easier with an eSIM phone plan, and switching devices is easier with a physical SIM. If you are not locked in on a particular wireless service provider, using an eSIM is a good option because it lets you jump from carrier to carrier with greater ease while you search for the right plan. 

Alternatively, if you are pretty comfy with your current carrier and are moving from device to device, a physical SIM is better for your transition. Transferring your account information from device to device is very easy if you have a physical SIM card. 

Should you Switch from Physical SIM to eSIM?

At this point, we would not worry too much about it. It is straightforward to switch from physical SIM to eSIM on the same phone. If you are changing devices, all you need to do is choose a mobile phone that supports eSIM cards, pick out a plan, and choose the eSIM option when you check out. 

If you switch carriers but keep your phone and phone number, switching from physical SIM to eSIM is similar to switching carriers and going from physical SIM to physical SIM. The main goal here is to switch your account. Switching carriers and keeping your device is a procedure where you must pick out a plan with your new carrier and start the switch on your device. As long as you have a phone with eSIM compatibility, you should have your new account up and running with no issues! Here are the general steps to switch carriers: 

  • Gather account information
  • Ensure your phone is unlocked and ready for transfer
  • Purchase a new plan with an eSIM card
  • Follow the company’s instructions on how to activate your new plan!

With physical SIM cards, phone activation occurs when you change your old SIM card for your new one. When switching to an eSIM, since there is no hardware to change, it all happens through your operating system. You can follow the on-screen prompts, which should instantly activate your phone! 

Whether you prefer physical SIM cards or eSIM cards, using your phone should be without issue. 

Key Takeaways

There was a lot of information in this article. Embedded SIM cards are awesome! They open up many opportunities across just about every industry for a new series of devices to better their workflow and optimize their progress. Regarding smartphone users, the difference between using eSIM and physical SIM on your personal device is next to none. No need to worry about which one is better for your phone! Before you go, there are a lot of questions about eSIM cards swirling around the Internet. Feel free to check out our FAQ if there’s still something on your mind. 

Frequently Asked Questions

There are a lot of questions surrounding these digital SIM cards, from their usage in personal smartphones, industry, and their development within the United States. We are highlighting these questions before wrapping everything up in hopes of answering all your questions regarding digital SIM cards that have recently grown in popularity. 

Which Phones Support eSIM? 

While the three major carriers in the United States support eSIM usage, phone manufacturers have resisted adopting this new SIM card. The primary phone manufacturers have eSIM-compatible devices but double-check before purchasing a phone with the express intention of utilizing its eSIM capabilities. A wide variety of devices have slots for two physical SIM cards, so if you want to activate multiple accounts on your device, that is another way to go. 

What Does eSIM Let You Do? 

Digital SIM cards allow for fast and digital changes to the wireless carrier that operates your device. Instead of physically removing and replacing your old SIM card with a new one, eSIM cards let you reprogram the SIM and change the service with a few taps on your screen. This is a significant boon for the manufacturing industry and other areas that operate large numbers of IoT devices, making software or carrier change much more efficient. 

Which US Carriers Support eSIM? 

While all three major US carriers support eSIM, they have not shown much interest in the new technology. The ease of using physical SIM cards for individual and family plans works very well, giving major carriers fewer incentives to switch to eSIM-only plans. 

Which Tablets and Laptops Support eSIM? 

All the iPads support eSIM and open up the opportunity for you to connect those devices to a mobile network with ease. There is limited laptop eSIM compatibility, but utilizing a tablet with a connected keyboard and trackpad is a great alternative. 

How Do You Activate an eSIM Phone Plan? 

While the specifics vary by carrier, activating an eSIM on your device is easy. There are support pages on T-Mobile, AT&T, and Verizon for finer details. There are two common ways to program the eSIM card and activate your eSIM phone plan. The simplest way is to sign up for a plan through an app on your phone or use that app to log in to your account and activate it that way. 

The other way is to generate a QR code from the carrier’s website and scan it with your cell phone. While a little more time-consuming, this is the most supported way to activate an eSIM phone plan on your device. 

What are the Pros and Cons of eSIM Phone Plans? 

The biggest downside to an eSIM phone plan is that switching the plan between multiple devices is harder. Instead of being able to physically remove the SIM card and slot it into the new device, you have to go through that same activation process every time. This is not a big deal for people who only change their phone once every few years, but it becomes increasingly tedious whenever you want to switch. 

While it is harder to switch between multiple devices, an eSIM card makes it easier to switch plans on a single device. Online activation is faster and easier than waiting for the new carrier’s SIM card. 

Are eSIM and 5G Related?

Nope! They are two new standards that developed simultaneously, and while there is no specific tie, they do influence one another. With the advent of 5G, networks became much more robust and could support a more significant number of devices in a given area. This has fueled more research and development into the Internet of Things and other tiny devices with an Internet connection. Internet of Things devices are common eSIM users, as their small footprint is perfect in tiny devices. As 5G networks continue to develop, we believe the market for eSIM devices (not necessarily phones) will also grow. 

Why are Carriers Slow to Adopt eSIM? 

A few years ago, almost all the major wireless carriers in the United States did their best to avoid the new eSIM technology. For a few years, they pushed physical SIM cards for, in broad strokes, business reasons. They figured that digital SIM cards would reduce foot traffic in their stores (this was several years ago) and decrease overall business. Recently, however, carriers are getting on board. Due to the pandemic, overall store traffic has decreased tremendously, and at this point, the big three US carriers are dipping their toes into the eSIM waters. Part of the reason they are not wholeheartedly aiding its development is that physical SIM cards remain excellent options for just about everyone.

Kyle Reyes
Kyles Reyes is a journalist from Pittsburgh, PA that specializes in the wireless industry, phone plan comparisons & advice.
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