What is an eSIM?

An eSIM is a SIM card built into your phone as a tiny chip. Instead of inserting a plastic card, you scan a QR code and a mobile plan downloads in minutes.

Sounds simple. And it is.

But there are a lot of questions around it. Does it change my number? Does my phone even have one? What happens if my phone breaks? How much data do I need?

This guide answers all of them. In it, you will learn:

• What an eSIM actually is, and what the e stands for
• What happens behind the scenes when you scan the QR code
• The 10-second trick to check if your phone supports eSIM
• How to keep your own number while using a travel eSIM
• How much data you really need for a trip
• The honest pros, cons, and safety facts

Let's dive right in.

What is an eSIM?

An eSIM, short for embedded SIM, is a SIM card that lives inside your phone. It is a small chip built into the phone itself.

It does the exact same job as the plastic card you used to push into a tray. It tells a mobile network who you are, so your phone can make calls, send texts, and use mobile data.

The difference is how you get a plan onto it.

With a plastic SIM, the plan is printed onto the card at a factory, and someone has to hand you the card. With an eSIM, the plan arrives over the internet. You scan a QR code, and a few minutes later you are connected.

An easy way to picture it

Think of a plastic SIM as a key.

You have to go and get it, carry it around, and swap it into the lock. Lose it, and you are stuck.

An eSIM is more like a smart lock. There is nothing to carry. You change the code from your phone, and it can remember several codes at once. That is why one phone can hold your home plan and a travel plan side by side.

Where did eSIMs come from?

eSIMs are newer than most people think:

• 2016Samsung releases the first device with an eSIM, a Gear S2 smartwatch.
• 2017Google Pixel 2 becomes the first phone with an eSIM.
• 2018iPhone XS and XR add eSIM, and it goes mainstream.
• TodayMost new flagship phones have one, and some ship with no SIM tray at all.

You may also hear about the iSIM. It goes one step further and builds the SIM into the phone's main processor. For you, it works exactly like an eSIM.

Here is the deal:

When you buy an eSIM, you are really buying a digital profile. That profile holds everything a plastic SIM used to hold: your identity on the network and the settings to connect to it.

Getting it onto your phone takes five steps. Your phone does most of them for you.

The three words that explain everything

You will see these in phone settings and support pages. Here is what each one means.

All of this follows one global standard from the GSMA, the mobile industry's body, called SGP.22. That is why the same process works on iPhone, Samsung, Pixel, and every other eSIM phone.

Do you need internet for this?

Once. The profile has to download, so you need Wi-Fi or another connection to install it. After that, the eSIM works on its own, and switching between eSIMs you have already installed needs no internet at all.

Three ways an eSIM gets onto your phone

The QR code is the most common way. But it is not the only one:

They all end the same way. The profile lands on the chip, and the new line shows up in your settings next to your other ones.

An eSIM and a physical SIM connect you to exactly the same mobile networks. Your signal and speed do not change.

What changes is how you get the plan, how many you can hold, and how easy it is to move.

For travel and second lines, the eSIM wins almost every time. A physical SIM still makes sense if your phone is older or you often move one line between phones.

Most phones released since 2018 support eSIM. But “most” is not “all”, so check before you buy.

The fastest way works on any phone:

1. 1Open your phone app, as if you were making a call.
2. 2Type *#06#.
3. 3Look for a number labelled EID.

If an EID shows up, your phone has an eSIM chip. Not every phone shows it there, so if you only see an IMEI, look in Settings, About phone, for an EID before you decide.

Two catches worth knowing

Your phone needs to be unlocked. A phone locked to one carrier may have an eSIM chip but refuse another provider's eSIM.

Some regional versions skip eSIM. For example, iPhones sold in mainland China use two physical SIMs instead.

Setting up an eSIM takes a few minutes and four steps. The menu names change a little from phone to phone, but the idea is always the same.

Installing and activating are two steps. Our guide to how to activate an eSIM explains both. Pick your phone for the exact taps:

This is the question almost everyone asks. So let's answer it straight:

Adding a travel eSIM does not replace your number. Your home SIM or eSIM stays on the phone. You simply choose which line does what.

How many eSIMs can one phone hold?

More than you will need. Most modern phones store several eSIM profiles, often five or more, and run one or two at the same time. iPhone 13 and later can even run two eSIMs together.

Will I still get texts from my bank?

Usually, yes. As long as your home line stays switched on, texts to your number keep arriving, including the one-time codes from your bank.

That is the big reason to keep your home line on while you travel. If you switch it off completely, those codes will wait until you switch it back on.

This is where eSIMs really shine. Before eSIMs, you had three options abroad, and all of them had a catch.

A travel eSIM gives you all four. You buy it before you go, install it at home, and switch it on when the plane lands.

Every destination has its own page with live plans and prices. Some of the most visited: a Japan eSIM for Tokyo and Kyoto, an eSIM for the United States, a UK travel eSIM, Turkey eSIM data and a Thailand eSIM for Bangkok and the islands.

How much data do you need?

For a week of normal travel, 3 to 5 GB is comfortable. Here is why: maps and messaging use almost nothing. Video is what burns through data.

See that gap? An hour of HD video can use as much as a whole week of maps and messages. So if you stream a lot, size up. If you mostly navigate and chat, a small plan goes a long way.

What happens when your data runs out?

With a prepaid eSIM, the data simply stops. There is no overage charge and no bill waiting for you at home.

To get back online, you add more data. Depending on the provider, that is a top-up on the same eSIM or a new plan you install the same way as the first one.

Your pre-trip checklist

Five minutes before you leave saves a lot of stress after you land:

• Dial *#06# and confirm your phone shows an EID.
• Check that your phone is unlocked.
• Buy a plan that covers every country on your route.
• Install the eSIM at home, on Wi-Fi.
• Label your lines Home and Travel.
• Turn off data roaming on your home line.

Then, when the wheels touch down, switch the travel line on, turn on data roaming for it, and you are online before you reach the gate.

How much does an eSIM cost?

Travel eSIMs are prepaid, and the price depends on the country, the data, and the days. You pay once. There is no contract and nothing to cancel.

At SimVala, plans start at $0.69. You pay in crypto, with no card, no email, and no ID.

The pros and cons

Is an eSIM worth it for you?

Here is the simple version:

Are eSIMs safe?

Yes. In one way, they are safer than a plastic SIM: nobody can pull an eSIM out of your phone.

The profile also downloads encrypted, so only your phone's chip can read it. What an eSIM cannot do is protect your accounts from phishing or SIM-swap scams, so keep using strong passwords and app-based two-factor codes.

eSIM glossary

eSIM

An embedded SIM: a chip in your phone that stores mobile plans you install by QR code.

eUICC

The technical name for the eSIM chip. It can hold several profiles.

EID

The eSIM chip's unique 32-digit number. Dial *#06# to see it.

Profile

A mobile plan in digital form, the eSIM version of a SIM card's contents.

SM-DP+

The provider's secure server that prepares and sends your profile.

Dual SIM

Running two lines on one phone, like your home SIM plus a travel eSIM.

Unlocked phone

A phone not tied to one carrier, so it accepts other providers' eSIMs.

iSIM

A SIM built into the phone's main processor. It works like an eSIM for you.

Sources

• GSMA: eSIM and consumer remote SIM provisioning
• Apple Support: Using Dual SIM with an eSIM
• Wikipedia: eSIM