How does an eSIM Work? Beginner’s Guide for Travellers

Planning to travel abroad and wondering how to stay connected without racking up a large phone bill? Understanding how eSIMs work could be the key to sorting that out before you even pack your bag.

An eSIM, short for embedded SIM, is a digital version of the traditional plastic SIM card. Rather than inserting a small chip into your phone, the SIM is built directly into your device.

This guide explains how eSIMs work, how to set one up, and why it can be a smart choice for UK travellers. And, we’ll also introduce you to the Wise debit card, which is designed for low-cost spending in 150+ countries.

It automatically converts your pounds to the local currency at the mid-market exchange rate, only adding a tiny, transparent conversion fee*.

Discover the Wise card

What is an eSIM?

Digital alternative to physical cards

A traditional SIM card is a small, removable plastic chip that links your phone to a mobile network. An eSIM does exactly the same job, but there is nothing physical to insert, lose, or swap.

eSIM stands for embedded SIM. It is a chip permanently built into your device during manufacturing. When you want to change networks or set up a new plan, you simply download a new profile directly to your phone. No visits to a shop. No waiting for a card in the post.

This makes eSIMs particularly useful for UK travellers. You can set up a local data plan before you leave home and be connected the moment you land at your destination.

How the embedded chip works

The eSIM chip inside your device stores one or more carrier profiles, which are digital versions of the information a physical SIM would normally hold. When you subscribe to a new mobile plan, the carrier sends a profile to your device over the internet.

You can store multiple profiles on a single eSIM and switch between them in your phone settings. For example, you could keep your UK number active on one profile while using a local travel plan on another. Many devices support dual SIM, which means both can run at the same time. This is useful if you want to stay reachable on your UK number while using cheaper local data.¹

How to set up an eSIM

Checking device compatibility

Not every phone supports eSIM, but most handsets released in the last three to four years do. Common eSIM-compatible models include:

• iPhones from the XS and XR onwards
• Samsung Galaxy S20 and newer models
• Google Pixel 3 and above
• Many newer iPads, smartwatches and some laptops

Not sure whether your phone is ready? Try dialling *#06#. If an EID (Embedded Identity Document) number appears on screen, your device supports eSIM.¹ You can also check under Settings, then General, then About on an iPhone, or visit the manufacturer's website for your model's specifications.

One thing to be aware of: your phone may need to be unlocked before you can add an eSIM from a different carrier. Check with your current provider before you travel if you are unsure.

Activating via QR code or app

Once you have chosen and purchased an eSIM plan, getting it set up is quick. The process usually works like this:

1. Your carrier emails you a QR code or directs you to their app
2. On an Android phone, scan the QR code and enter the confirmation code sent separately by the carrier
3. On an Apple device, turn on Wi-Fi, open Settings and follow the on-screen steps

Some providers let you activate everything through their app alone, without needing a QR code at all.²

Installation timelines and requirements

You will need a Wi-Fi connection to install and activate your eSIM. After that, it works just like any other mobile plan.

Most eSIMs are activated within a few minutes. It is worth doing this at home before you travel, so you have time to contact the carrier if anything does not go to plan. Some plans only start counting down your data allowance once you connect to a local network abroad, so check the terms of your specific plan when you buy.²

Benefits of using eSIM for travel

Switching between multiple carrier profiles

One of the most practical benefits of an eSIM is being able to switch between carrier profiles without touching anything physically. Everything is managed in your phone settings.

This is particularly handy for longer trips or journeys through multiple countries. Rather than buying a new SIM at every destination, you can install several regional profiles before you leave and switch between them as needed. Many UK users keep their home number active on one profile while using a local data plan on another, so they do not miss any important calls.

Cost savings compared to roaming

Using your UK mobile plan abroad can be expensive. Some UK networks charge between £6 and £8 per day just to access your usual data allowance while roaming.¹ Over a two-week trip, that quickly adds up.

Buying a local eSIM plan for your destination could work out at a lower cost for many routes and plan types, depending on the provider and country. You pay a flat, predictable rate for a set amount of data, often for a fixed number of days. It is worth comparing a few options before you travel to find what suits your trip.

Enhanced security and theft protection

With a traditional SIM card, someone who steals your phone could remove the SIM and use it in another device. Because an eSIM is permanently embedded, it cannot be taken out. This significantly reduces the risk of SIM swapping, a type of fraud where criminals use your number to access accounts and messages.

Because eSIMs cannot be physically removed, they may reduce certain risks associated with SIM theft or SIM swapping. That said, it is still important to use a strong passcode and keep your phone software updated.

eSIM and device hardware

Space-saving benefits for smartphones

Removing the physical SIM tray frees up space inside your handset. Manufacturers can use that extra room for other improvements, such as a larger battery, a better camera setup, or a stronger internal frame.

Some of the latest iPhone models sold outside the US are eSIM-only, with no SIM tray at all. This trend is expected to grow as more manufacturers move in the same direction. For UK users, dual eSIM support on these devices means you can still run two numbers on one handset.³

Environmental impact of reducing plastic waste

Every traditional SIM card is a small piece of plastic that also needs a card, packaging, and delivery. Across millions of SIMs issued each year, that adds up to a considerable amount of material waste.

eSIMs create none of that waste. There is no card to produce, no packaging to throw away, and no delivery required. For anyone looking to make small, everyday choices that are a little better for the planet, switching to eSIM is a straightforward one.

Popular eSIM providers for UK travellers

Several travel eSIM providers now offer prepaid data plans for UK travellers. The right option depends on your destination, trip length, and how much data you expect to use.

Some of the most popular eSIM providers include:

• Airalo - known for broad country coverage and flexible prepaid plans
• Nomad - popular for regional data packages and competitive pricing
• Holafly - offers unlimited data plans in selected destinations
• aloSIM - provides flexible short-term travel plans
• Saily - newer provider focused on international connectivity

If you are comparing providers directly or want to know about the best options for different countries, read our guides to:

• Nomad vs Airalo
• Saily vs Airalo
• Best eSIM for Japan
• Best eSIM for Turkey
• Best eSIM for Egypt
• Best eSIM for India
• Best eSIM for New Zealand

Managing your travel costs

Local data plans versus roaming

When you go abroad, you have two main options for staying connected:

• Roaming on your UK plan
• Buying a local plan through an eSIM provider

Roaming is convenient but can be unpredictable in cost. Many UK carriers add a daily fee to your plan, and your data allowance while roaming is often lower than at home. Going over your roaming allowance can lead to unexpected charges.

A local eSIM plan gives you a fixed cost upfront. You choose how much data you need and for how many days. Most plans can be purchased online in minutes and activated with a QR code before you leave. For frequent travellers, dedicated eSIM providers offer regional and global plans that work across multiple countries.

Heading abroad soon? Choose Wise for low-cost international spending

Open a Wise account online and you can order the Wise debit card for a one-time fee of £7. You can use this clever card in 150+ countries.

It automatically converts your pounds to local currency whenever you spend using the mid-market exchange rate, only adding a tiny, transparent conversion fee* – or it’s free if you already have the local currency in your Wise account.

You also get free ATM withdrawals up to 250 GBP (or currency equivalent) each month. There’s no limit on the number of free withdrawals. Wise will not charge you for these withdrawals. After that, a 2.69% variable fee applies, but additional charges may occur from independent ATM networks.

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FAQs

Can I use an eSIM on any phone?

No, not all phones support eSIM technology. Most smartphones released in the past three to four years are compatible, including many iPhones, Samsung Galaxy and Google Pixel models. To check your device, dial *#06# and look for an EID number, or review your phone's specifications on the manufacturer's website.

Do I lose my original phone number?

No. Adding an eSIM plan does not remove your existing number. Most eSIM-compatible phones support dual SIM, so you can run your UK number alongside a travel plan at the same time. You will still be able to receive calls and texts on your usual number while your eSIM handles data.

How long does it take to activate?

Most eSIMs activate within a few minutes of scanning the QR code or completing the in-app process. You will need a Wi-Fi connection during setup. It is worth activating your eSIM before you travel so you have time to contact the carrier if anything does not work as expected.

Is an eSIM more secure than a physical SIM?

In most cases, yes. An eSIM cannot be physically removed from your device, making it much harder for someone to steal it or carry out a SIM swap attack. That said, it is still important to keep your device software updated and use a strong screen passcode.

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Sources used:

1. Apple Support - Use eSIM while travelling internationally with your iPhone
2. Three UK - Discover eSIM: What is an eSIM and how does it work?
3. Sim Local - What Is an eSIM in the UK? Everything You Need to Know

Sources last checked: 28-Apr-2026