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But what is an eSIM for? (And is it worth switching?)

New phones offer it, carriers push it, but nobody explains what changes. The eSIM in plain words: what it is, when it's worth it, and the one case where the plastic SIM is better.

Andrea Bissi · · 3 min read

But what is it for?
Level
beginner
Time
5 minutes
What you need
Nothing, just curiosity

When you buy a new phone, the carrier asks: “physical SIM or eSIM?”. Most people answer at random, and you can see why. Let’s clear it up.

In plain words

SIM (short for Subscriber Identity Module): the little plastic card that tells the network "this phone belongs to Andrea, with this number". eSIM (embedded SIM, a SIM built in): exactly the same thing, but written into a chip already inside the phone, no card. You activate it by scanning a QR code your operator gives you. The code does not contain the SIM, it tells the phone where to go and fetch your profile and download it.

What actually changes

In daily use, nothing. You call, text and browse as before.

You feel the difference when you have to activate a line, change it or add a second one: with an eSIM you do it in five minutes from the sofa, scanning a QR code the carrier emails you, with no waiting for delivery and no trip to the shop.

When it’s a blessing

  1. You travel outside Europe. You buy an eSIM online for the country you're going to, you activate it before you leave, and the moment you land you're already connected, while keeping your home number active for calls. The price varies a lot with the destination and the data included, so it's worth comparing two or three offers. For me it's the number one reason to switch.
  2. You want two numbers on one phone. One personal, one for work, without carrying two phones around. Almost all recent phones handle a physical SIM plus an eSIM, or two eSIMs.
  3. Your phone gets stolen. An eSIM can't be pulled out and slotted into another phone, so a thief can't move your number onto a device of their own. Careful, though, because the bigger risk is a different one, and it's there with a plastic SIM too. If the phone is unlocked, or the thief watched you type your code, they can read your bank's messages right there. So use a long code, and ring your carrier to block the line as soon as you notice.

The one case where it’s worse

If you change phones often, or keep a spare in a drawer, the physical SIM is handier. You pull it out and slot it in. With an eSIM you have to do the transfer instead, which is simple on iPhone and recent Samsungs, clunkier on other Androids, and some carriers charge a few euros. And if the phone breaks completely, you can’t move the number to an old handset until you get the eSIM reissued.

Don't worry:

There's no difference in reception or speed. Nor in battery use, if you keep a single line; if you keep two active at once the phone uses a touch more, because it stays connected to two networks. And you can go back to a plastic SIM by asking your carrier, though some charge for the swap.

The verdict

If your phone supports it, I'd take the eSIM: it's convenient, harder to walk off with, and unbeatable when travelling. Keep the plastic SIM only if you swap phones every month, or if you need to be able to move your number to an old model without any fuss.

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