eSIM: what is it and how does it work for travel

What an eSIM is

An eSIM is a digital SIM card, built into the phone as a chip instead of inserted as a removable physical card. Technically, it’s a subscriber identity module installed via software on an eUICC chip soldered into the device. The GSMA maintains three versions of the standard: SGP.22 for consumer phones, SGP.02 for machine-to-machine use, and SGP.32 for the Internet of Things, published in 2023.

A device can store more than 20 eSIM profiles, though usually only 1 or 2 stay active at the same time.

This isn’t a recent technology. The first consumer device with an eSIM was the Samsung Gear S2 smartwatch, in 2016; the first smartphone followed a year later with the Google Pixel 2, while Apple added support with the iPhone XS and XR in 2018. From 2018 onward, most phones and tablets on the market support it.

How a travel eSIM gets activated

Activation almost always runs through a QR code or the carrier’s app, generated after buying a prepaid plan: it can be done before departure or already on arrival. The step travelers forget most often is that a Wi-Fi connection or a hotspot is needed to finish the activation: without a network available, the process stays stuck.

Real-world example: someone landing in a country outside the European Union without having activated the eSIM in advance, and without Wi-Fi at the airport, is stuck until a network turns up. Someone who instead buys a local physical SIM at a shop can activate it even without a data connection already in place, because the shop staff register and insert the card.

On an unlocked iPhone XS or later, with no SIM restrictions, two eSIMs can stay active together, with one chosen in Cellular settings to handle data while the other stays active for calls and texts. On the Pixel 7 and later, Google allows up to two simultaneous eSIM profiles, if the carrier allows it. From iOS 26 onward, an iPhone automatically turns off the travel eSIM on return and switches back to the main line.

Inside the European Union, the question often doesn’t come up

To see how a phone’s data actually travels from one country to another, it helps to revisit how the internet works: a data plan moves from a traveler’s home operator to local ones through roaming agreements, regardless of whether the card is physical or digital.

According to the European Commission, the “roam like at home” rules have been a reality since June 15, 2017: travelers within the European Union use their home Italian operator’s data at the same rate as at home, with no surcharges. The same applies across the European Economic Area (Iceland, Liechtenstein, Norway), and from January 1, 2026, in Ukraine and Moldova too.

That guarantee isn’t unlimited. A fair use policy, adopted on December 15, 2016, lets operators apply a data cap in roaming if the domestic price is lower than the EU regulatory ceiling, and monitor usage over a four-month period to check whether time spent abroad exceeds time at home. The wholesale rate operators charge each other was €1.30 per gigabyte plus VAT in 2025, dropped to €1.10 in 2026, and will settle at €1.00 per gigabyte plus VAT from 2027.

Outside the European Union, where the choice really counts

Outside the EU, the European Economic Area, Ukraine and Moldova, a home Italian operator’s roaming can get expensive: this is where buying a travel eSIM or a local physical SIM starts to make practical sense. Some travel eSIM providers cover plans in over 190 countries or regions, convenient for anyone visiting several stops on the same trip.

Anyone still putting a trip together, alongside finding cheap flights and a hotel reservation, can add the data connection choice to the same pre-departure checklist: plan coverage, the activation country, and whether the phone being packed — along with a power bank for the flight to avoid running out of battery — actually supports eSIM.

eSIM vs SIM: the comparison table

Which one makes more sense mainly depends on the destination country rather than the phone model: an eSIM skips the card that has to be inserted and swapped, while a local physical SIM works without an existing data connection, activated over the counter in a shop.