How Does an eSIM Work? A Plain-English Guide
Last checked: September 2026
An eSIM is a SIM chip built into your phone instead of a removable card. A mobile plan is downloaded to that chip as a profile, usually by scanning a QR code over Wi-Fi. Your phone can store several profiles, and you choose which ones are active. eSIM is a GSMA standard used by networks worldwide.
What an eSIM is
An eSIM is a SIM chip built into the phone (an eUICC) instead of a removable card. Because it is soldered in place, there is no tray to open and no plastic to lose. The chip holds your mobile plans as digital profiles, and eSIM is a GSMA standard used by networks worldwide.
The chip itself is called an eUICC. It is a small component on the phone's circuit board, and it does the same job as the chip inside a plastic SIM: it identifies your line to the network. The difference is that you never handle it. Instead of swapping cards, you add or remove plans in software.
A plan stored on the chip is called a profile. A profile contains the details your phone needs to connect, such as the network identity and the settings for calls and data. You can keep more than one profile on the phone and switch between them in your settings.
Because the chip cannot be removed, a lost phone's eSIM cannot be taken out and used in another phone. That is one practical difference from a plastic SIM, which can be moved to a spare handset.
How an eSIM gets onto your phone
A mobile plan is downloaded to the chip as a profile, usually by scanning a QR code over Wi-Fi. The download needs an internet connection, so do it before you travel or while you still have Wi-Fi. Once the profile is installed, it stays on the phone until you delete it.
Here is the usual process:
- Make sure the phone is connected to Wi-Fi.
- Open the eSIM settings on your phone and choose the option to add a plan.
- Scan the QR code supplied with your plan, or enter the details manually if you are given them.
- Follow the prompts to download and label the profile.
- Choose which line to use for mobile data and which to use for calls and texts.
The exact menu names differ by phone model and by country, so the wording on your screen may not match another person's. If you get stuck, our guide on how to install an eSIM walks through the screens step by step.
Using an eSIM and a physical SIM together
One phone can store several eSIM profiles, and which ones are active at the same time depends on the model. Many phones can run one eSIM alongside a physical SIM, so you can keep your home number live while a travel plan handles data. The phone must be carrier unlocked to use an eSIM from a different provider.
This is the setup most travellers use. Your home SIM stays in the phone for calls, texts and bank codes, while the eSIM carries your data. You set the default line for data in your phone's settings, and the other line stays available for incoming messages.
If your phone is locked to a network, an eSIM from another provider will not work. You can check the phone is unlocked before you buy a plan. It is also worth confirming the handset supports eSIM at all, which you can do with our guide to check your phone supports eSIM.
Which phones support eSIM
iPhone XS, XS Max and XR (2018) and later support eSIM, and iPhone 14 and later models sold in the USA have no physical SIM tray. Google Pixel 3 and later and Samsung Galaxy S20 and later support eSIM, depending on the model and country. Support varies, so check your exact model.
The USA versions of iPhone 14 and later rely on eSIM only, so there is no tray to fall back on. Elsewhere, most recent iPhones have both an eSIM and a tray. On Android, support arrived with the Pixel 3 and the Galaxy S20 families, but not every model in every country includes it.
Because support depends on the model and the market it was sold in, the safest step is to check the phone's own settings or the manufacturer's specification for your exact handset.
eSIMs for travel
A travel eSIM is data only: keep your home SIM for calls, texts and bank codes. You install the travel profile before you fly, then switch it on when you land. This avoids roaming charges on your home line and gives you data from the moment you arrive.
A data only plan means your regular number still works for messages, including the one time codes banks send. You simply choose the travel eSIM as the line for mobile data. If you want to know what is available where you are going, you can browse travel eSIMs by country.
Install the profile at home over Wi-Fi rather than at the airport, when you may be tired or short of time. Once it is on the phone, it waits until you enable it.
Questions, answered
How does an eSIM work without a card?
An eSIM is a SIM chip built into the phone, called an eUICC. Your mobile plan is downloaded to it as a profile, usually by scanning a QR code over Wi-Fi. The chip then identifies your line to the network, exactly as the chip inside a plastic SIM does.
Can I use an eSIM and a normal SIM at the same time?
One phone can store several eSIM profiles, and which ones are active at the same time depends on the model. Many phones can run one eSIM alongside a physical SIM, so you can keep your home number for calls and texts while a travel plan handles data.
Do I need Wi-Fi to install an eSIM?
Yes. A mobile plan is downloaded to the chip as a profile, usually by scanning a QR code over Wi-Fi. The download needs an internet connection, so install the profile before you travel or while you still have Wi-Fi. Once installed, it stays on the phone until you delete it.
Which phones support eSIM?
iPhone XS, XS Max and XR (2018) and later support eSIM, and iPhone 14 and later models sold in the USA have no physical SIM tray. Google Pixel 3 and later and Samsung Galaxy S20 and later support eSIM, depending on the model and country.
Can I move an eSIM to another phone if I lose mine?
No. Because the chip cannot be removed, a lost phone's eSIM cannot be taken out and used in another phone. That is a practical difference from a plastic SIM, which can be moved to a spare handset. You would need a new plan for a replacement phone.