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Travel eSIMs: How to Choose One

Installing an eSIM by QR code in front of an airport departures board

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Travel eSIMs: How to Choose One

By Iggy Simcox|Last updated: 22 July 2026|How we test

A travel eSIM is the least interesting purchase you will make before a trip, and one of the few that ruins your first day if you get it wrong. Here’s how to choose one in about five minutes, and what the comparison sites tend to skip.

What an eSIM actually replaces

Three options exist when you land somewhere new. Roam on your home plan and accept the bill. Find a shop and buy a local physical SIM, which means queueing, a passport, and sometimes an hour you don’t have. Or install an eSIM before you leave and land with data already working.

The third option won on convenience, not price. A local physical SIM is often still cheaper per gigabyte, particularly for long stays. What an eSIM buys you is not having to solve a problem in an unfamiliar airport at midnight, which, depending on the trip, is worth considerably more than the price difference.

Two things to check before you buy anything: your phone must support eSIM, and it must be carrier-unlocked. Most phones from roughly 2019 onward do support it, but a handset bought on contract may still be locked even years later. Dial *#06#. Check: if an EID number appears alongside the IMEI, your phone has eSIM hardware.

đź“· SCREENSHOT NEEDEDDial-pad screen showing *#06# result with the EID line circled. iPhone or Android, real device.

Apple maintains an official guide to eSIM on iPhone, and the industry body behind the standard, the GSMA, explains how eSIM works under the hood.

The four things that actually differ

Which network it lands on

This is the one that matters most and gets discussed least. An eSIM provider is a reseller. They buy wholesale access to a local carrier and sell it to you. So “Airalo in Japan” is really “a Japanese carrier, resold”. If that underlying carrier has poor coverage where you’re going, no amount of app polish fixes it.

Good providers name the network on the plan page. Ambiguity there is a mild red flag, and worth checking against the carrier’s own coverage map for the region you’ll be in, not the country as a whole.

Whether “unlimited” is unlimited

It generally isn’t. Most unlimited plans carry a fair-use threshold, after which speeds drop sharply, sometimes to a level where maps still work but video doesn’t. That’s a perfectly reasonable product, and for a lot of travellers it’s the right one. It’s just not what the word implies.

Read the fair-use policy before buying an unlimited plan, and treat the daily threshold as the real number.

Data-only, or calls and texts too

Most travel eSIMs are data-only. You keep your home number for calls and SMS, and use data for everything else. This is fine right up until a bank or airline sends a verification code to your home number while it’s roaming. Check that your home SIM can still receive SMS, or you can find yourself locked out of the booking you’re trying to change.

Top-ups and expiry

Plans expire, usually 7 to 30 days from activation. Some let you top up in-app and extend; some require buying a fresh plan. If your dates are uncertain, top-up flexibility is worth more than a slightly lower headline price.

How to pick, quickly

Match the plan to the trip rather than hunting for the cheapest per-gigabyte figure. The saving between providers on a one-week trip is usually a couple of pounds, and it is not worth twenty minutes of comparison.

  • Short trip, one country: buy a small local plan for that country. Regional plans cost more and you won’t use the coverage.
  • Multi-country trip: a regional plan avoids buying and activating a new eSIM at every border.
  • Heavy user, or you refuse to think about data: an unlimited plan, after you’ve read the fair-use threshold.
  • Long stay, cost-sensitive: an eSIM for the first day or two, then a local physical SIM once you’ve landed and have time.

Who we cover

We currently look at four providers in this category, chosen for catalogue breadth, price, and how they handle the awkward cases above:

  • Airalo: the widest country catalogue and the category default
  • Saily: newer, clean app, built by the team behind NordVPN
  • Holafly: unlimited-data plans, for people who won’t count megabytes
  • Nomad: frequently the cheapest per gigabyte

eSIM guides

The rest of the stack

An eSIM is one of four things worth sorting before you fly. A travel VPN gets your home services working from abroad, a no-fee travel card stops you losing 3% on every purchase, and travel insurance covers the one risk that actually matters. All four together are on our travel tech stack.

Where to start: Airalo. The widest catalogue in the category at 200+ countries and regions, a clean app, round-the-clock support, and in-app top-ups make it the provider you can default to without researching every destination. Switch to Holafly if you refuse to count data (its unlimited plans run full speed for roughly 3 to 5 GB a day per 2026 reporting, then slow down), to Nomad when price per gigabyte is everything, and to Saily if you want an ad and tracker blocker built into the data. In a handful of destinations the resold network flips this answer, which is exactly what our country guides are for. The full head-to-head reasoning lives on our travel tech stack.

How we handle claims we haven’t tested first-hand is set out in how we test.

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