What is … an eSIM?

If you’ve bought a new cell phone in the past couple of decades, you’re probably already familiar with the SIM—the little thumbnail-sized card that connects to your carrier’s cellular network. However, in recent years, smartphone manufacturers and carriers have started replacing SIMs with something called an eSIM

What is an eSIM?

The “e” in eSIM stands for “embedded,” which makes sense as this is a SIM card that stays inside your phone and can’t be removed. It performs the same function as a traditional SIM card but has the potential to make things a lot simpler for most smartphone users. Almost any new phone you buy nowadays features eSIM technology, including the new iPhone 15. In fact, the iPhone 15 doesn’t even have a physical SIM card slot available, and all iPhone 15 users need to transfer to eSIM — hinting where the technology is going. Pretty soon, eSIMs could become the standard, with physical SIM cards gradually fading out of use

What are the advantages of an eSIM?

It’s easier to switch networks: an eSIM makes it much easier to switch mobile networks. Instead of ordering a new SIM, waiting for it to arrive, and then inserting it into your phone, you can switch to a different network with a phone call or online. You also won’t need to hunt for a SIM ‘ejector tool’ to remove the old SIM from your phone

You can temporarily change to another network: up to five virtual SIM cards can be stored on one eSIM at a time. This means you can quickly switch between different networks if you find yourself in an area without a signal on your usual network

Where eSIMs really come into their own is by simplifying the process of switching to a local network while travelling outside the EU. Just buy an eSim for the country you are visiting online in advance, adjust your phone’s settings and it gives you a data allowance overseas (you can use internet-based apps such as WhatsApp for calls and texts). And to be clear, this is to use alongside your physical UK Sim card, meaning you don’t need to change your number while abroad – and will still receive calls and texts, though you may be charged by your home network. They’re far more convenient than other ways to beat roaming charges, such as grabbing a local SIM, which involves finding a phone shop when you get to your destination, swapping out your UK SIM, getting a new number and making sure you don’t lose your original precious tiny piece of plastic before you get home

It allows you to have more than one SIM: eSIMs also offer the same advantages as dual-SIM phones with two slots for traditional plastic SIMs, the most obvious being that you can have two phone numbers on one device

This can be handy if you want one number for personal use and another for business but don’t want to carry two phones around. You’ll be able to receive phone calls and texts on both numbers at all times and choose which SIM to use for making calls, sending text messages, or using data

It uses less physical phone space: Another advantage of eSIMs is that they will eventually negate the need for a physical SIM card and its tray. Smartphone manufacturers could potentially use this space to increase a phone’s battery size or add more features to a handset. Fewer holes in a handset also mean more protection from moisture and dust, so fewer breakdowns

There’s also the potential to make handsets smaller in some cases. But the real space advantage is for wearables such as smartwatches, as people don’t want to wear an enormous device on their wrist. The Apple Watch from Series 3 and later already support eSIMs, as do the Samsung Gear S2 and upwards smartwatches

What are the disadvantages of an eSIM?

There are a couple of potential downsides to eSIMs, though

It’s not as easy to switch devices quickly: at the moment, if your handset stops working, you can easily remove the SIM and put it in another phone, keeping your number and contact information (assuming your contacts are stored on the SIM)

This will be much trickier with an eSIM – although storing information and contacts in the cloud is designed to make it easy to transfer data such as contacts from one phone to another

There’s no place to hide: you also can’t remove an eSIM from a device, which may be viewed as a downside if you have concerns about your movements being tracked. But this may also be an advantage, as it means phone thieves can’t easily hide the location of a stolen phone

Do all smartphones have an eSIM?

The most recent smartphones and wearables have an eSIM. These include:

Apple iPhones: iPhone XR, iPhone XS, iPhone 11, iPhone 12, iPhone 13, iPhone SE (2nd generation), and iPhone 14 and later
Samsung Galaxy: S24 / S24+ / S24 Ultra, Galaxy S23 / S23+ / S23 Ultra, Galaxy S22 / S22+ / S22 Ultra, Galaxy S21 / S21+ / S21 Ultra, Galaxy S20 / S20+ / S20 Ultra
Google Pixel: 3a and 3 XL or later
Motorola’s Razr: (only an eSIM, it doesn’t have a physical SIM card)
Samsung Gear: S2 and Gear S3 smartwatches and later
Apple Watch: Series 3 and later