What is an eSIM, and how does it work when you travel from the UK?

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You may not need one. Ten of the 15 UK networks we checked include Europe on some plans, and all 15 treat the Republic of Ireland like home (checked on 24 October 2026; see roaming in Europe).

What is an eSIM?

An eSIM is a chip built into the phone that holds your mobile plan as a downloaded profile, so there is no card to post or swap. Apple says an iPhone can “manage up to eight or more eSIMs” (Apple, checked on 24 October 2026).

Technical sources call the chip an eUICC and its identifier the EID; both are in the glossary. One fact from them matters for travel: an eSIM profile can be added, switched off and deleted in the phone’s settings.

A physical SIM is a card you hold, and the two do the same job. We set out the advantages and disadvantages of each in eSIM vs physical SIM.

How does an eSIM work?

You scan a QR code, or type the details by hand, with the phone on Wi-Fi; the phone downloads the eSIM profile and joins the network it names. Apple’s UK page gives both routes for iPhone (Apple, checked on 24 October 2026).

The code comes from your network or from the seller. Our order e-mail carries the QR code and, beside it, the details for typing in by hand.

A phone can hold several profiles and run one or two at a time. Apple says “You can have two eSIMs active at the same time on supported iPhone models” (Apple); for Dual SIM with two eSIMs, that means iPhone 13 models and later (Apple).

Each UK network does its own set-up. EE, for example, gives an eSIM on the phone, in its app, or by a QR pack sent by post (checked on 24 October 2026, EE eSIM help).

How does a travel eSIM work abroad?

A travel eSIM is a data plan for the country or region you visit. On almost all our plans you have 365 days to install it, and on most of them its validity starts on first connection to a network at the destination, not when you buy it; check the activation rule shown on your plan.

Our regional plans are data-only eSIMs. A few local plans add local calls, none lets you call home, and no plan comes with a UK number. There is no ID check.

Your UK network’s own eSIM is different: it is your UK line, with your UK number, calls and allowance. A travel eSIM sits next to it as a second line.

In practice:

1. Buy the plan and install it at home on Wi-Fi. The install window is stated on each plan.
2. Fly. Leave the line switched on, with data roaming set as the install instructions say.
3. Land. The phone joins a local network; on most of our plans the days start then (each plan shows its activation rule).

Our step-by-step guide covers iPhone and Android: how to install a travel eSIM.

Ofcom’s advice to people using a phone abroad includes this line: “Consider a different SIM … or an ‘e-SIM’” (updated 6 July 2026, Ofcom). That is Ofcom’s consumer advice, not an endorsement of us.

Turkey: buy and install your eSIM before you travel. eSIM shops, including ours, may not open on Turkish networks (Turkey eSIM).

Can I keep my UK number and WhatsApp?

Yes. A travel eSIM adds a second line, so your UK number and your WhatsApp account stay as they are. On a dual SIM phone, the UK line takes calls and texts and the travel line carries data (Apple).

Apple says “Your iPhone can use one mobile data network at a time” (Apple). With only the travel eSIM on, “FaceTime and iMessage will continue to work on your home line” (Apple, checked on 24 October 2026).

WhatsApp uses mobile data, so it runs on whichever line you pick for data. The travel eSIM has no number, so the number on your WhatsApp account does not change.

One trap: calls and texts on the UK line abroad are still charged by your UK network. The menu steps and the other dual SIM traps are in keep your UK number.

What are the disadvantages of an eSIM?

An eSIM needs a compatible, unlocked phone, a travel eSIM is usually data only, and a deleted eSIM can need a replacement from your network. EE’s help page, for one, sends you to its app for that (checked on 24 October 2026).

• Compatibility and lock. An older phone has no eSIM, and a phone locked to one network will not take another provider’s. On iPhone, Settings → General → About should show “No SIM Restrictions” next to Network Provider Lock (Apple). Menus can differ by model and software version.
• Data only. Our regional plans carry no minutes or texts. A few local plans allow local calls, and none lets you call home. Keep your UK line for calls.
• Deleting is not a free undo. A deleted eSIM can need a replacement from the network that issued it, so check its steps first. EE, for example, sends you to its app to “Replace my SIM/eSIM” if you have deleted your eSIM or lost the phone (EE). Install the new phone’s eSIM before you delete the old one; how to transfer an eSIM has the paths.
• Turkey. Buy and install your eSIM before you travel. eSIM shops, including ours, may not open on Turkish networks.
• Safety of the code. O2 says: “Never share your QR code with anyone and keep it somewhere safe” (O2, checked on 25 October 2026). Treat a travel eSIM QR code the same way.

A Pixel can also ask for your password before an eSIM is erased: Settings → Security → Advanced → Confirm SIM deletion (Google, checked on 25 October 2026). Menus can differ by phone and Android version.

Does my phone take an eSIM?

Dial *#06# on the keypad: if an EID number appears, your phone takes an eSIM. EE and Vodafone both give this check (checked on 24 October 2026, EE, Vodafone).

By make, Apple’s rule is “An iPhone XS, iPhone XS Max, iPhone XR or later” (Apple); Apple lists exceptions for some models sold in China mainland, Hong Kong and Macao, so on an iPhone bought abroad run the *#06# check and look for Add eSIM in Settings. Google’s is “Pixel 4 and later: All phones work with eSIM” (Google).

Samsung says “Some Galaxy phones come with an eSIM”, so check your model. On a Galaxy the EID is on the box or in Settings → About phone → Status (Samsung). Menus can differ by model and software version.

Then check the lock, as above. The model-by-model list is on eSIM compatible phones.

When don’t you need an eSIM?

Skip it if your plan already covers the trip. Ten of the 15 UK networks include Europe on some plans, and all 15 include the Republic of Ireland (checked on 24 October 2026).

On a network with a daily charge, a short trip costs that charge for each day you use the phone. Our network-by-network Europe table puts every daily charge and included limit side by side.

A travel eSIM earns its place outside the included zone, above your plan’s limit, on a longer trip, or when you want a data line separate from your UK allowance. For Europe, see the Europe eSIM.

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