# What Is an eSIM?

> An eSIM is a SIM card built into your phone that you activate by downloading a profile. What that actually changes when you travel, and what it does not.

Using an eSIM · Published 2022-06-16 · Updated 2026-08-21 · 5 min read

Page: https://esimradar.com/blog/what-is-an-esim

![A man in a red jacket looking at his phone on a city street at night, lit by the traffic and shopfronts behind him.](https://esimradar.com/blog-images/what-is-an-esim/hero-17580078-1280.webp)

*Nothing about this scene requires a shop. An eSIM is bought and installed where you are standing.*

An eSIM is a SIM card that is already inside your phone. Instead of pushing a piece of plastic into a tray, you download a profile — a small file that tells the phone which network to join and proves you are allowed to. The hardware was soldered in at the factory; buying an eSIM buys you permission to use it.

That single change — plastic to download — is the whole story. Everything people find useful about eSIMs follows from it, and so does everything they find annoying. It is also not any one company’s feature: eSIM is [an industry specification from the GSMA](https://www.gsma.com/solutions-and-impact/technologies/esim/about/), the body operators use to agree on how phones and networks talk to each other.

## What it changes when you travel

You can buy a local data plan before you leave and switch to it when you land, instead of hunting for a shop at the airport or paying your home carrier’s roaming rate. Activation takes a couple of minutes on hotel wifi.

You also keep your normal number. Nearly every eSIM-capable phone can hold your home SIM and a travel eSIM at once, with the travel plan carrying data and your usual number still receiving calls and texts. That is the part most people actually want. Some recent models have no tray at all — Apple lists [which iPhone and iPad models are eSIM only](https://support.apple.com/en-us/118569), and [Google says the same of a US Pixel 10](https://support.google.com/pixelphone/answer/9449293) — which changes nothing here except that both lines are then eSIMs.

## What it does not change

A travel eSIM is almost always [data only](https://esimradar.com/faq). It gives you an internet connection, not a phone number in the country you are visiting. Everything that runs over the internet works normally — maps, messaging, email, calls in WhatsApp or FaceTime. What does not work is anything that needs an SMS to a local number.

> **Note:** This is the one thing worth checking before you buy. If your bank sends verification codes by SMS, they go to your home number, so you need that line reachable — which usually means leaving your home SIM active for texts while the eSIM carries data. Plans that include a number exist and are labelled as such.

## Does your phone support it?

Most phones sold since about 2020 do, and the ones that do not are covered in [which phones support eSIM](https://esimradar.com/blog/esim-phones). Rather than trust a compatibility list, though, check the phone itself — the answer is definitive and takes ten seconds:

- iPhone: Settings → General → About. If there is an [Available SIM](https://esimradar.com/faq) or EID entry, the phone has an eSIM.
- Android: Settings → Network & internet → SIMs → Add SIM. A "Set up an eSIM" option means yes — that is the wording in [Google’s instructions for setting up a new eSIM](https://support.google.com/pixelphone/answer/16115470).
- Either: dial \*#06#. If [an EID](https://esimradar.com/blog/eid-number) appears alongside the IMEI, the phone has eSIM hardware.

Two caveats the spec sheet will not tell you. A phone bought on contract may be carrier-locked, which blocks other networks whatever the hardware supports. And the market a phone was sold in matters: [Apple states that in mainland China only the iPhone Air and iPhone 17e support eSIM](https://support.apple.com/en-us/118227) at all, so an otherwise identical handset bought there will not take one.

## How you actually install one

1. Buy the plan. You get a QR code, usually by email, within a minute or two.
2. Scan it from the phone’s eSIM setup screen while on wifi. This downloads the profile.
3. Label the line something you will recognise later, like the country name.
4. On landing, turn the travel line on for data and leave your home line on for calls and texts. Turn data roaming on for the travel line — it is roaming from that network’s point of view, even though you are paying local rates.

Install before you fly, activate when you land. Almost every plan’s validity starts when the eSIM first connects to a network, not when you buy it, so installing early costs you nothing. The full walkthrough, including what to do when the code will not scan, is in [how to install an eSIM](https://esimradar.com/blog/install-esim).

## What to compare when buying

Headline price is the wrong number. A $4 plan with 1 GB costs four times as much per gigabyte as an $8 plan with 5 GB, so [price per GB](https://esimradar.com/faq) is what makes plans of different sizes comparable. Then check the validity window, whether you can top up mid-trip, and — for anything advertised as unlimited — the daily cap after which speeds drop.

You can see every provider we track scored on exactly those terms by [destination](https://esimradar.com/country) or by [provider](https://esimradar.com/provider).

## Common questions

### Can I keep my normal number while using a travel eSIM?

Yes, on nearly every eSIM-capable phone. Your home SIM stays active for calls and texts while the travel eSIM carries data. Turn your home line’s data roaming off so it cannot quietly bill you.

### Does an eSIM work without wifi?

Installing one needs an internet connection, so do it before you travel. Once the profile is on the phone, it activates over the mobile network without wifi.

### Can I move an eSIM to another phone?

Usually not freely. A profile is tied to the device that downloaded it, and transferring means asking the provider to reissue it. Some support in-place transfer between recent iPhones; most do not.

### What happens when the data runs out?

The connection stops. Most providers let you top up the same eSIM rather than buying a new one — worth checking before you buy, because the ones that do not force you through the whole install again.

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More guides: https://esimradar.com/md/blog.md

Compare plans by destination: https://esimradar.com/md/destinations.md