What are eSIMs and how do they work?
eSIM is a shortened version of embedded SIM, where SIM is an acronym for Subscriber Identity Module. So, an eSIM is an Embedded Subscriber Identity Module. The little thing that allows your phone to connect to your cellular provider’s network. When you buy a new phone, you pop out your SIM card, drop it into the new phone, and cellular service is a go.
That’s going to change with eSIM, because as the “embedded” part of the name suggests, this is actually built into the phone’s mainboard. It’s rewritable, similar to an NFC chip, and will be compatible with all the major carriers, regardless of what type of network they use.
The Apple Watch 3 and Pixel aren’t the only devices using eSIMs. Cars do too—we’ve all seen a connected car at this point, and you may have ever wondered where its SIM card is. The short answer is that it’s using an eSIM. That’s one application where it really just makes sense.
Other manufacturers of connected devices—usually smarthome devices—are also using eSIMs. It just makes sense: it’s less hassle for the customer, more connection options for the manufacturer. And for those types of applications, it really is a win-win. When we start talking about bringing this tech to smartphones, however, its gets a little fuzzier.
The Benefits of eSIMs
That may sound inconvenient, but the benefits pretty strongly outweigh the cons . First off, since device manufacturers won’t have to accommodate a SIM card slot in their phones, they’ll have even more flexibility in terms of design. With the SIM card actually embedded into the device’s internal hardware, bezels could theoretically shrink, phones could perhaps get slightly thinner without sacrificing battery, and a lot more. That’s precisely why Apple chose to use an eSIM in the Watch 3—it makes so much sense in a small form factor device like a smartwatch.
Also, this could be a game changer for international travelers who have to swap SIM cards, services, or even carry more than one phone to stay connected. Instead of having to pop into a local cellular provider store to get a new SIM card when travelling abroad, imagine just being able to make a quick phone call and you get coverage. All without having to jump through hoops or change phones.
The Challenges of eSIMs
There is a catch, though: adoption. Before we can make the leap over to eSIM, every major carrier is going to have to agree that eSIMs are the future. Then, phone manufacturers will have to follow suit. If you know how this industry works, those kind of things take time.
But it starts with one carrier, which will then grow to two, and so forth. Google’s Pixel 2 is the first smartphone to use an eSIM, but that’s only if you’re using the phone on Project Fi. For all others, it still uses a traditional SIM.
Switching phones can be a bit more time-consuming. You can swap your SIM card out in seconds, where the change to eSIMs will take longer to do the same thing.
Update about T-mobile
T-Mobile announced the launch of its new T-Mobile eSIM app (via VentureBeat), designed to allow iPhone XR, XS, and XS Max users to sign up for T-Mobile as a second carrier via the eSIM feature in the newest iPhones.
The company says the service is designed for international visitors, although existing T-Mobile customers can also use the app to select a prepaid option. Your phone needs to be running iOS 12.1.1 to use the eSIM on any of these carriers.