How to Set Up a Travel eSIM Before You Fly

A travel eSIM is a SIM built into your phone, so there's no plastic card to swap. You buy a data plan online, add it to your phone, and you've got local data abroad without paying your home network's roaming charges. Your usual number stays put for calls and texts.

Setting one up takes about ten minutes. Doing it at home, before you fly, saves you from fiddling with settings at a baggage carousel on airport wifi. Here's the step-by-step.

before you buy: two quick checks

1. does your phone support eSIM? Most phones from the last few years do, but not all. Open your phone's dialler and type *#06#. If you see a number labelled EID, your phone supports eSIM. You can also look in your settings: on an iPhone it's under General, then About; on Android, search settings for "eSIM" or "SIM manager".

2. is your phone unlocked? A travel eSIM won't work on a phone locked to your network. Phones sold in the UK since December 2021 should already be unlocked. If yours is older, ask your network to unlock it before you go.

Bonus check: do you need one at all? Some UK mobile plans include roaming in Europe or further afield. Check what yours includes and what it costs per day. If roaming is free on your plan for where you're going, you may not need an eSIM. If it isn't, or you're going further afield, an eSIM is usually the cheaper route. And if roaming matters to you long-term, it's worth filtering for it next time you compare SIM-only deals.

step 1: pick the right plan

Compare travel eSIMs on four things:

where it works. One country, a region, or global. Check every country you'll touch, including stopovers.
how much data. If you'll use hotel wifi for the heavy stuff, maps and messaging don't use much. Streaming and hotspotting use a lot.
how long it lasts. Make sure the validity covers your whole trip.
when the clock starts. Most plans start counting down when you first connect abroad, not when you buy. Some start on a fixed date. Check, so a plan bought early doesn't run out mid-holiday.

step 2: install it at home, on wifi

After you buy, you'll get a QR code or a link in an app. Then:

connect to your home wifi. Installing needs an internet connection.
scan the QR code in your phone's mobile data or SIM settings (or tap the install link).
give the eSIM a clear label, like "travel", so you don't mix it up with your main line.
leave it switched off for now, if your phone gives you the option, so it doesn't start counting down early.

One important tip: don't delete the eSIM once it's installed. Many can't be reinstalled from the same QR code, and you'd be buying another one.

step 3: switch over when you land

This is the bit people get wrong, so take it slowly:

turn on the travel eSIM line.
set it as your mobile data line. Your phone will ask which line to use for data. Pick the eSIM.
turn data roaming ON for the eSIM. It sounds backwards, but most travel eSIMs connect as a "roaming" service, so they need this on to work. You won't be charged extra for it, as the eSIM's data is already paid for.
turn data roaming OFF for your main line. This is what stops your home network charging you for data abroad.

You can keep your main line switched on for calls and texts if you want to be reachable on your usual number. Just remember that calls and texts on it are charged at your home network's roaming rates. Apps like WhatsApp and iMessage carry on working over the eSIM's data, using your usual account.

if it doesn't connect

Try these in order:

check data roaming is switched on for the eSIM line
check the eSIM is selected as your mobile data line
turn aeroplane mode on for ten seconds, then off again
restart your phone
check your provider's app or email for any settings it asks you to add

If it still won't play ball, contact the eSIM provider's support. Most have chat in their app.

while you're away

Keep an eye on your data in the provider's app. If you're running low, many plans let you top up, and it's usually cheaper than buying a whole new plan. Hotel and café wifi is your friend for anything big, like downloading films for the flight home.

when you get home

Switch your mobile data back to your main line and turn the travel eSIM off. Once you're sure you won't use it again, you can delete it. Some plans last long enough to reuse on a later trip, so check before you do.

the short version

dial *#06# and look for an EID to check your phone supports eSIM
make sure your phone is unlocked
compare travel eSIMs by coverage, data, validity and start date
install at home on wifi, and don't delete it
when you land: eSIM on, eSIM for data, roaming on for the eSIM, roaming off for your main line

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