The eSIM
Guy Blog

The one-line answer

An eSIM is a SIM card that lives inside your phone as a chip — no physical card, no tray, no fiddling with a pin tool at the airport. You download a plan wirelessly and your phone connects to a local network, just like a normal SIM would.

How it actually works

Traditional SIM cards are little plastic chips that store your network credentials — who you are, which network you're on, and what plan you're paying for. An eSIM does exactly the same thing, but it's soldered into your phone at the factory. Instead of swapping cards, you download a profile (a small data file) that tells the eSIM which network to connect to.

When you buy a travel eSIM, you receive a QR code. Scan it from your phone's settings, and the profile installs in under a minute. Your phone can store multiple profiles simultaneously — so your UK number and a US travel plan can coexist without any faff.

Does my phone support eSIM?

Most modern phones do. The short list:

• iPhone XS (2018) and all models after
• Google Pixel 3 and later
• Samsung Galaxy S20 and later (varies by region)
• Most flagship Android phones from 2021 onwards

The easiest check: go to Settings → About Phone and look for "SIM Status" or "EID" — if you see an EID number, you have an eSIM.

eSIM vs physical SIM for travel

For travel, the eSIM wins on almost every count. No hunting for a SIM shop when you land. No risk of losing your UK card. No scissors-and-tape job trying to cut a nano SIM. You buy the plan from your sofa, scan the QR code, and you're done.

Find a plan for your destination →

What roaming actually costs in 2026

Since Brexit, UK networks lost automatic EU roaming rights. Most have reinstated some form of free or cheap EU roaming, but outside Europe it's a different story. For the USA, Australia, Japan and most of Asia, roaming add-ons typically run £10–£15 per day.

On a 10-day trip to New York, that's up to £150 just for data. And you usually get a capped daily allowance — run out and you're either throttled or charged again.

A real comparison: USA trip, 10 days

• EE roaming add-on: £10/day × 10 = £100 for 500MB/day (throttled after)
• Vodafone roaming: £12/day × 10 = £120 for 1GB/day
• Yesim eSIM (10GB, 30 days): approx £14 total

The eSIM costs roughly the same as one day of roaming and gives you more data over the whole trip. The maths aren't close.

When roaming makes sense

Short trips of one or two days where you don't need much data, and your network offers free EU roaming that covers your destination, are the cases where a roaming add-on is fine. For anything longer, or anywhere outside the EU, a travel eSIM is almost always the better call.

Compare data plans →

Before you start

Make sure you've already purchased your eSIM plan and have the QR code to hand — either on screen or printed. You'll need a Wi-Fi or mobile data connection to complete the download. Do this at home before you travel.

The steps

1. Open Settings on your iPhone.
2. Tap Mobile Data (or "Cellular" on US devices).
3. Tap Add eSIM or Add Mobile Plan.
4. Choose Use QR Code and scan the code from your purchase email.
5. Tap Continue through the confirmation screens.
6. When asked, set your primary line (your UK number) and label the new eSIM as "Travel" or the country name.
7. Set the eSIM as your default for data when prompted.

That's it. The eSIM will show as installed. It won't activate until your phone connects to a network in your destination country.

What if the QR code doesn't scan?

If your phone can't read the QR, Yesim also provides a manual activation code you can type in. Look for "Enter details manually" on the same screen. Alternatively, screenshot the QR code to a different device and scan it from there.

Find your travel eSIM →

Why you need a plan for the US

Unlike EU destinations, there's no roaming reciprocity between the UK and US. Every major UK network charges a daily add-on — usually between £10 and £15 — to use your UK data allowance in America. On a two-week holiday, that's potentially £200 just for data.

How US eSIM coverage works

Travel eSIMs for the USA work by roaming on established US networks. Yesim partners with major US carriers to provide coverage across all 50 states — including Hawaii and Alaska. You'll have 4G/LTE in most cities and towns, with 5G available in major metro areas depending on your handset.

Which plan should I pick?

For most US holidays, a 10GB plan over 30 days is the sweet spot. It's more than enough for navigation, social media, streaming the odd video and general browsing. If you're working remotely or streaming a lot, step up to a 20GB plan. Light users (maps and occasional messaging only) can get away with 3–5GB.

Will my iPhone work on US networks?

Yes, with one caveat. iPhones sold in the US since 2022 are eSIM-only (no physical SIM slot). If you bought your iPhone in the UK, you'll have both a physical SIM and eSIM — both work fine in the US. Just make sure to set the eSIM as your default data line before you board.

See USA eSIM plans →

The quick check

Go to Settings → General → About (iPhone) or Settings → About Phone (Android). Look for a field called EID. If it's there, your phone has an eSIM. No EID means no eSIM support.

iPhones with eSIM

• iPhone XS, XS Max, XR (2018) — first iPhones with eSIM
• iPhone 11, 11 Pro, 11 Pro Max
• iPhone 12 series, iPhone 13 series, iPhone 14 series
• iPhone 15 and 16 series — eSIM supported worldwide
• iPhone SE (2nd gen, 2020) and later

Note: US-model iPhones from iPhone 14 onwards are eSIM-only with no physical SIM tray.

Android phones with eSIM

• Google Pixel 3 and later (all models)
• Samsung Galaxy S20, S21, S22, S23, S24, S25 series
• Samsung Galaxy Z Fold and Z Flip series (most models)
• Motorola Razr 2019 and later
• OnePlus 12 and later
• Huawei P40 and later (limited support)

What about carrier-locked phones?

Some phones bought on contract — especially through EE, Vodafone or O2 — may be locked to that carrier's eSIM profile. This means you can't add a third-party travel eSIM until the phone is unlocked. Most UK networks will unlock your phone for free after 30–90 days. Contact your network's customer service to request an unlock.

Find a plan for your phone →

1. Installing it at the airport

eSIM installation needs a data or Wi-Fi connection to download the profile. If you're already at the departure gate with no data left, you're stuck. Always install your eSIM at home, at least a day before you travel.

2. Not setting it as the default data line

Having an eSIM installed doesn't mean it's active for data. Go into Settings → Mobile Data → Mobile Data (iPhone) or Settings → Network → Mobile Network (Android) and select your eSIM as the default. Otherwise you'll be using your UK data allowance at roaming rates without realising it.

3. Buying too little data

A 1GB plan sounds fine until you use Google Maps for a full day of exploring. Maps, social media and the odd Google search add up fast. For a week's travel, 5GB is a safe floor. Go for 10GB if you're streaming anything or video calling home.

4. Choosing a plan that doesn't cover your whole trip

If you're there for 12 days, don't buy a 7-day plan assuming you can top up. Topping up mid-trip is possible but not always seamless. Buy a plan that covers your full stay from the start, or pick a 30-day plan for flexibility.

5. Not keeping your UK SIM active

Travel eSIMs are data-only. If you remove or disable your UK SIM, you lose your UK number for calls and texts. Leave your physical SIM in, keep it active, and let the eSIM handle data. Both work simultaneously without any issue.

Find the right plan →

Before you start

Make sure your phone supports eSIM (check for an EID in Settings → About Phone) and that it isn't carrier-locked to a single eSIM profile. You'll need Wi-Fi or mobile data to complete the download. Do this at home before you travel.

Samsung Galaxy (S20 and later)

1. Go to Settings → Connections → SIM Manager.
2. Tap Add Mobile Plan.
3. Tap Scan Carrier QR Code and scan your Yesim QR code.
4. Follow the on-screen prompts to confirm and activate.
5. Set the eSIM as your preferred data SIM in SIM Manager.

Google Pixel (3 and later)

1. Go to Settings → Network & Internet → SIMs.
2. Tap the + button to add a new SIM.
3. Choose Download a SIM instead? at the bottom.
4. Tap Next, then scan the QR code.
5. Set as preferred for mobile data when prompted.

Find your travel eSIM →

How data adds up when travelling

Most people massively underestimate how much data they use when they're out and about all day. At home you're on Wi-Fi most of the time. Abroad, your phone is pulling from mobile data constantly — maps, messages, social media, payments, everything.

Data usage by activity (per hour or session)

• Google Maps navigation: ~5–10MB per hour
• Instagram/TikTok browsing: ~100–200MB per hour
• WhatsApp messages: minimal — under 1MB for text
• WhatsApp voice call: ~3MB per minute
• WhatsApp video call: ~25MB per minute
• Streaming video (SD): ~700MB per hour
• Streaming video (HD): ~1.5–3GB per hour

Recommended data by trip type

Light user (maps, WhatsApp text, occasional browsing) — 3GB per week is comfortable.

Average user (maps, social media, occasional calls, some browsing) — 5–8GB per week.

Heavy user (all of the above plus streaming, video calls, working remotely) — 15GB+ per week.

Which plan to choose

For most one-week holidays, a 10GB plan is the safe choice — enough buffer that you won't run out, without spending on data you won't use. For two weeks or more, go for a 20GB or 30-day unlimited plan.

Compare plans →

What makes a good eSIM destination?

Two things: strong local network coverage, and competitive pricing for travel eSIM plans. Some countries have great networks but high wholesale data costs — meaning travel eSIMs are still expensive. The best destinations combine both.

Top tier: excellent coverage, great value

USA — major network partners across all 50 states, competitive pricing on 30-day plans. One of the best value eSIM markets right now.

Japan — exceptional LTE and 5G coverage, even in rural areas. eSIM plans are well-priced and data goes a long way.

Thailand — outstanding coverage in Bangkok and all tourist areas. One of the cheapest data markets in Asia, and eSIM plans reflect that.

UAE — Dubai and Abu Dhabi have excellent 5G coverage. Regional plans covering GCC countries are good value if you're island-hopping.

Strong but worth checking before you go

Australia — great coverage in cities and along major highways, but rural and outback areas can be patchy. Urban travellers will be fine.

Mexico — solid in Cancún, Mexico City, and tourist zones. Remote areas less reliable. Worth downloading offline maps before you leave the hotel.

India — massive improvements in coverage over the last two years. Cities and major tourist routes are well-served. Mountain regions and some rural areas still spotty.

Ones to watch in 2026

South Korea and Singapore are consistently ranked among the world's best mobile networks — and eSIM availability has expanded significantly. Both are worth picking a dedicated regional plan over a global one.

Find a plan for your destination →