eSIM explained: how it works, which phones support it, and using it abroad

Calling abroad · Published 2026-10-24

An eSIM is a SIM card that you download instead of insert. The chip is soldered inside the phone, and the operator's subscription is installed on it as a software "profile". The result is the same as a plastic SIM; the difference is how you get it and how many you can keep.

What is actually inside the phone

The hardware is an embedded Universal Integrated Circuit Card, or eUICC. Like a physical SIM, it securely stores the credentials that identify you to the network. Unlike a physical SIM, it can hold several operator profiles and can receive new ones over the air. The process is called Remote SIM Provisioning, and the GSMA's specifications define how it works so that any operator's profile can be installed on any compliant device. For consumer phones the relevant specification is SGP.22; a separate architecture (SGP.32) covers connected objects.

How you install an eSIM

• QR code: the operator gives you a code that contains the address of its provisioning server and an activation code. The phone scans it and downloads the profile.
• Operator or travel app: the app triggers the download for you.
• Carrier activation at purchase: some phones receive a profile automatically when bought from, or linked to, an operator.
• Transfer from an old phone: both iOS and Android offer transfer tools, but the operator must support them; otherwise you request a new eSIM from the operator.

An internet connection, usually Wi-Fi, is needed during installation. A QR code is generally single-use: once a profile has been installed and then deleted, you may need a new code from the operator, so do not delete an eSIM casually before a trip.

Which phones support eSIM

Most recent flagship and mid-range smartphones from Apple, Google and Samsung support eSIM, as do many other brands, but not every model in every country. Apple introduced eSIM with the iPhone XS, XS Max and XR in 2018, and since the iPhone 14 in 2022, iPhones sold in the United States have no physical SIM tray at all. Apple's eSIM support page explains that an iPhone can store eight or more eSIMs and use two lines at the same time. On Android, support depends on model and region; manufacturers list it in the specifications.

Two points are easy to miss:

• Carrier locks. A phone locked to one operator will usually refuse other operators' eSIMs, exactly as it would refuse their physical SIMs. Ask your operator to unlock it before travelling.
• Regional variants. Some models are sold without eSIM in certain markets. Check the exact model number, not just the name.

More on why a phone that "supports" a feature may still not work with a given network is in our guide to device support.

Dual SIM with eSIM

Many phones can keep two lines active at once, for example a physical SIM and an eSIM, or two eSIMs. This is usually "dual SIM dual standby": both numbers can receive calls, but while you are on a call on one line, the other may be unreachable or go to voicemail. You choose which line provides mobile data, and which line is the default for calls and messages.

For travellers this is the main attraction: keep your home number for calls, SMS codes and messaging apps, and use a cheaper local or travel eSIM for data. Make sure "data roaming" is turned off on the home line if its roaming prices are high, and on for the travel eSIM if its provider requires it (many travel eSIMs technically roam on partner networks).

Travel eSIMs: what to check before buying

1. Data-only or with a number? Most travel eSIMs give data only. Calls then go through apps, or through Wi-Fi calling on your home line where your operator allows it over another provider's data connection.
2. Which local networks? The provider resells access to local operators. Coverage in cities is usually fine; in rural areas it depends on the partner network.
3. Validity and activation. Some packages start counting days when installed, others when you first connect in the destination country.
4. Tethering, speed caps and fair-use limits on "unlimited" offers.
5. Refund policy if the eSIM will not install on your phone.

Security and practical risks

• SIM swap fraud. eSIMs do not remove the risk of someone convincing your operator to move your number to their device. Protect your operator account with a strong password and a PIN or passphrase, and prefer app-based or hardware authentication to SMS codes for important accounts.
• Lost or broken phone. You cannot move an eSIM by swapping a card into a spare handset. Know how your operator reissues an eSIM, and keep the account login handy when travelling.
• Do not share QR codes. An unused activation code can be installed by whoever scans it.

Should you switch?

If your phone supports it, an eSIM is at least as capable as a plastic SIM and more flexible for travel. Keep a physical SIM if you change phones often and your operator makes eSIM transfers awkward, or if you rely on an older device without eSIM. For a comparison with other ways of staying connected, see calling abroad: the options.