You have three ways to get mobile data abroad: keep your home plan and roam, buy a local SIM card at the destination, or install a travel eSIM before you leave. Each one is the cheapest option in some situations and a bad choice in others. The difference comes down to where you live, where you are going, and how much data you actually use.
This guide explains what an eSIM is, how to check that your phone can use one, when you do not need one at all, and the mistakes that leave people standing in arrivals with no signal.
What an eSIM actually is
A SIM, physical or not, holds the credentials your phone uses to identify itself to a mobile network. An eSIM is a chip soldered into the phone that can store those credentials as downloadable profiles instead of on a plastic card. The standard is written by the GSMA, the mobile industry body, and the idea is remote provisioning: the operator sends you a profile (usually via a QR code or an app), the phone downloads it, and the profile then behaves like a SIM.
In practice that means:
- You can buy and install a plan from your sofa, days before you travel.
- Your phone can hold several profiles and switch between them in settings.
- Many phones can run two lines at once, so your home number stays reachable while a travel eSIM handles data.
On iPhone, Apple says two eSIMs can be active at the same time on supported models, and a phone with a SIM tray can combine a physical SIM with an eSIM.
Does your phone support it?
Two conditions must both be true: the phone has eSIM hardware, and it is not locked to a carrier.
iPhone. Apple lists eSIM support on the iPhone XS, XS Max, XR and later, with exceptions for phones sold in mainland China, where only a few recent models support it (Apple). To check for a carrier lock, go to Settings, General, About, and look for "No SIM restrictions" next to Carrier Lock.
Android. Support depends on the model and sometimes the market it was sold in. A quick test many guides recommend is dialling *#06#: if a 32-digit EID (the eSIM's identifier) appears, the phone has an eSIM chip (esimDB describes the same check). It works on iPhones and on many Android phones, Samsung included; on others the EID sits under Settings, About phone. On Pixels you can also look under Settings, Network and internet, SIMs, for an option to add an eSIM. A missing EID is not conclusive, so check the manufacturer's spec page if unsure.
A phone bought on contract may still be locked. The carrier can usually unlock it once the contract terms are met, but that takes time, so do it weeks before the trip, not at the gate.
When you do not need any of this: EU roam like at home
If your SIM is from an EU country and you are travelling inside the EU, you may already have what you need. Under the EU's roam like at home rules, you pay domestic prices for calls, texts and data in other EU countries. Your Europe lists the coverage as the EU plus Iceland, Liechtenstein and Norway, and also Moldova and Ukraine. The scheme was extended until 2032.
There are limits worth knowing:
- Fair use. Roaming is meant for travel, not living abroad. Your operator can monitor use over a four-month period and add capped surcharges if you spend more time and data abroad than at home.
- Cheap and unlimited plans. If your data costs less per gigabyte than the regulated wholesale cap, which steps down each year from €1.30 per GB (plus VAT) in 2025 to €1 from 2027 (Your Europe), the operator can set a lower roaming allowance and must tell you how much it is. "Unlimited at home" often means a fixed allowance abroad.
- Switzerland, the UK and Turkey are not covered, even though they are a short flight away. Your Europe notes that roaming outside the zone "can be expensive".
- Ships and planes. On a cruise ship or an aircraft with onboard mobile service, your phone may connect to a satellite network that is outside EU price rules. Your Europe advises turning roaming off or using flight mode.
For an Italian flying from Cagliari to Barcelona, a travel eSIM usually adds nothing. For the same person flying to Zurich, Istanbul or London, it often saves real money.
UK travellers are in a different position. Since Brexit, UK operators are no longer bound by the EU rules. As of April 2026, Which? reported that EE (£2.59 a day), Three (£2 a day) and Vodafone (£2.57 a day) charge to roam in Europe unless roaming is already in your contract, while O2 does not. Check your current tariff before assuming Europe is free.
The three options compared
| Home plan roaming | Local SIM | Travel eSIM | |
|---|---|---|---|
| Setup | Nothing, or a roaming add-on | Buy at the airport or a shop, often with ID | Buy online, install before leaving |
| Works on arrival | Yes | After you find a shop | Yes, if installed and set up beforehand |
| Your home number | Stays active | Removed while the SIM is in (unless dual SIM) | Can stay active alongside |
| Local phone number | No | Yes | Usually no (most are data only) |
| Typical cost profile | Free inside a roaming zone, expensive outside | Cheapest per GB, especially for long stays | Mid-range, priced per GB or per day |
| Best for | Trips inside your roaming zone | Stays of several weeks, heavy data use | Short and medium trips outside your zone |
A local SIM still wins in some cases. If you are spending a month somewhere, need a local number for deliveries, restaurant bookings or ride apps, or want large amounts of data, a local prepaid plan is often the better deal. Many countries require identity registration for local SIMs, so expect to show a passport.
How much data do you need?
Most people overestimate. Messaging, maps and browsing use little. Video and hotspotting a laptop use a lot. For a sense of scale, Netflix says its high quality setting uses up to 1 GB per hour in standard definition, up to 3 GB per hour in HD and up to 7 GB per hour in 4K, while its lowest setting uses up to 0.3 GB per hour. One evening of streaming in a hotel with poor Wi-Fi can use more than a week of maps and messages.
A practical way to size it:
- Open your phone's cellular or mobile data statistics and look at a normal week at home.
- Subtract what you will not do abroad (long commutes with podcasts, for example) and add what you will (more maps, more photos uploaded to the cloud).
- Pick a plan a bit above that number, from a provider that lets you top up from inside its app.
You can cut usage further by downloading offline maps for your destination, setting photo backups to Wi-Fi only, and turning off automatic app updates on mobile data.
Setting up a travel eSIM without drama
- Install it at home on Wi-Fi. The profile download needs an internet connection. Doing it in arrivals on weak airport Wi-Fi is the most common way this goes wrong.
- Read when the plan starts. Some providers start the validity clock when you install, others when the eSIM first connects to a network at the destination. If it starts at install, set it up a day or two before departure, not two weeks.
- Label the lines. Name the travel profile something obvious so you do not mix it up with your home line.
- Set which line uses data. Point mobile data at the travel eSIM. On your home line, turn data roaming off so it cannot quietly rack up charges. Keep it on for calls and texts if you want bank codes by SMS.
- Turn on data roaming for the travel eSIM. This catches people out: most travel eSIMs connect through partner networks, so the phone treats them as roaming. If roaming is off for that line, you get signal bars and no data.
- Do not delete it early. With many providers, a QR code can only be installed once. Delete the profile mid-trip and you may need support to reissue it.
Common pitfalls
- Expecting a phone number. Most travel eSIMs are data only. Calls work through WhatsApp, FaceTime or similar apps; ordinary calls and SMS still go through your home line and are billed by your home operator.
- Hotspot restrictions. Some cheap plans block tethering. If you need to work from a laptop, check before buying.
- "Unlimited" with a catch. Many unlimited travel plans slow you down sharply after a daily threshold. Read the fair use terms.
- Regional plans with gaps. A "Europe" plan may cover the EU but not Switzerland, the UK or Turkey. Check the list of countries, not the name of the plan.
- Carrier-locked phones. The eSIM installs, then refuses to connect. Check the lock first.
- Banking apps and SIM checks. A small number of banking apps check the active SIM. Keep your home line active alongside the eSIM rather than switching it off entirely.
Planning the rest of the trip
Connectivity is one part of arriving abroad in decent shape. If you are crossing several time zones, our guide to jet lag science and fixes covers what actually helps. If things go wrong with the flight itself, EU261 compensation may apply. And if you are still choosing where to go, how to find direct flights explains how to see every nonstop route from your home airport, such as Cagliari.
Frequently asked questions
Can I keep WhatsApp on my home number while using a travel eSIM?
Yes. WhatsApp is tied to the number you registered with, not to the SIM providing data. Point mobile data at the travel eSIM and WhatsApp keeps working on your usual number.
Will I still receive SMS codes from my bank?
If your home line stays active, yes. In the EU roaming zone that costs nothing extra. Outside it, receiving texts is often free but not always, so check your operator's roaming page.
Is a travel eSIM worth it inside the EU?
Usually not if your SIM is from an EU or EEA country, because roam like at home already gives you domestic pricing. It can make sense if your home plan has a small roaming allowance or your SIM is from outside the EU.
Can I use an eSIM on a phone without eSIM hardware?
No. Some providers sell physical SIM cards that can be programmed with travel plans, but a phone without an eSIM chip cannot download an eSIM profile.
When should I install the eSIM?
Before you leave, on reliable Wi-Fi. Check whether the plan's validity starts at installation or at first connection abroad, and time the install accordingly.