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Not too long ago I was scrolling through the contact list on my phone, and I realized I had about six entries for myself. Tom-Indonesia, Tom-Italy, Tom-Spain, Tom-Turkey, Tom-Thailand, Tom-Australia. All those identities were leftovers from when I’d bought physical SIM cards to get cellular data in various countries for whatever phone I was carrying at the time. (Remember Blackberry?) That process was a pain. You had to find someone who was selling SIMs. You sometimes had to contact someone else – such as the national phone carrier – to get the SIM activated and connected to the network. You had to notify your correspondents that you now had an Indonesian phone number and your American number was suspended. And, you had to be sure not to lose that tiny tool that opened your phone’s SIM slot when you needed to put your American SIM back in the phone. Oh yeah, you had to remember where you put your American SIM.
None of that happens anymore. An eSIM — a digital SIM card built right into your phone — lets you buy a local data plan online from an app before you even board the plane. No kiosk, no tray, no ejector tool, no surprise bill. Your regular phone number stays active for calls and texts the whole time. We covered this briefly in our best travel apps post, but it’s become such a core part of how we travel that it deserves its own guide — especially the parts nobody explains clearly: which plan to buy, how far ahead to set it up, and what to do if it doesn’t work the second you land.
What an eSIM Actually Is (In Plain English)
Think of an eSIM as a SIM card with no card. (BTW, SIM stands for Subscriber Identity Module, in case you were wondering.) It’s a small program built into your phone’s hardware that a provider “writes” a data plan onto, over the internet, instead of you inserting a physical chip. You buy a plan through an app, scan a QR code or tap an install button, and your phone now has a second line running alongside your home number.
That second line is what handles data — maps, email, translation, browsing — while your home number keeps working for calls and texts, assuming you leave roaming off or minimal on that line. Most modern phones can run both lines at once, which is the whole trick.
Is Your Phone Compatible? Check This First
Before you buy anything, confirm your phone supports eSIM. Most phones from the past several years do, but not all — and some carrier-locked phones (particularly certain U.S. carrier versions sold with two physical SIM slots instead) don’t.
- iPhone: iPhone XS and later (2018 or newer) support eSIM. Go to Settings > General > About and look for an entry labeled “Digital SIM” or an EID number — if you see one, you’re set.
- Android: Most Google Pixel phones (Pixel 3 and later) and Samsung Galaxy S20 and newer support eSIM. Go to Settings > Network & Internet > SIMs, and look for an option to add an eSIM or download a SIM.
If you’re not sure, it’s worth five minutes to check before your trip rather than discovering the problem at the gate. Your phone also needs to be unlocked by your home carrier — if you’re still under contract or financing a phone, check that first too.
Step-by-Step: Setting Up Your eSIM Before You Fly
Here’s the process, in order, the way we actually do it. Do this a few days before you leave, while you’re on your home Wi-Fi — not at the airport.
- Download the app. Pick a provider (our picks are below) and download it from the App Store or Google Play.
- Create an account. Just an email and password — no need to enter your home phone number or carrier details.
- Choose your destination and data amount. As a rough guide: 1–3GB per week covers maps, email, and messaging with light browsing. If you plan to stream video, use your phone as a hotspot for a laptop, or make video calls, go with 5–10GB or an unlimited plan.
- Purchase the plan. This just buys and reserves it — it doesn’t start your data clock yet in most cases (more on that below).
- Install the eSIM. The app will either show a QR code to scan with your phone’s camera, or offer a one-tap “easy install” button if you’re installing on the same phone you’re using. Do this while connected to Wi-Fi.
- Label the new line. Your phone will ask you to name it. Call it something obvious — “Italy Data” or “Saily eSIM” — so you can find it later in a settings menu that will otherwise just show two lines that look identical.
- Set your line priorities. This is the step people skip and then wonder why their bill looks odd. In your phone’s cellular settings, keep your home line set as default for Calls and iMessage/Texts, and set your new eSIM as default for Cellular Data. Turn data roaming ON for the new eSIM line, and make sure it stays OFF for your home line.
One Important Distinction: Installing vs. Activating
Most eSIM plans don’t start counting your data validity from the moment you buy or even install them — they start when the eSIM first connects to a network at your destination. That means you can safely install your eSIM a few days ahead of your trip without burning through your plan sitting in your hotel room at home. We do this the night before we fly, so we land with data already working — we just don’t turn on that line’s data/roaming until we’re actually there or about to land. Check your specific provider’s app to confirm how their validity window works before you rely on this.
Our Picks: Saily, Airalo, Holafly, and Yesim
We’ve used all four of these on trips across dozens of countries. They all work well — the differences are mostly about coverage style and data structure.
| Provider | Best for | Why we’d pick it |
|---|---|---|
| Saily | Most trips, general use | The one we reach for most often. Wide country and regional coverage, and you can bundle in a VPN for extra peace of mind on hotel or cafe Wi-Fi. |
| Airalo | Multi-country trips | The widest range of countries and regions of the group, plus regional bundles that cover several countries on one plan — handy if your itinerary crosses borders. |
| Holafly | Heavy data users | Plans lean toward unlimited data rather than fixed gigabyte caps, which suits anyone who streams, hotspots, or just doesn’t want to think about a data counter. |
| Yesim | Single-country trips | A dependable, well-trusted option when your whole itinerary is one country — straightforward plans without the regional-bundle overhead. |
None of these require you to commit to just one. We’ve installed a second provider’s eSIM as a backup on longer trips, just in case one has a coverage gap in a particular region.
Crossing Borders: Handling Multi-Country Trips
If your trip covers more than one country, you have two reasonable approaches. The simplest is a regional or global plan — Airalo in particular offers these — that covers a whole group of countries on one data allowance, so you’re not swapping anything as you cross a border.
The alternative is going country by country, which is where we like Yesim: their single-country plans, like this eSIM for France, are simple to set up and they’ve built a strong trust reputation, so it works well when you know your route well ahead of time — France this week, Portugal the next. The tradeoff is remembering to switch your phone’s default data line at each border. For a quick two- or three-country trip, we’ll usually just take the regional plan and not think about it again; for a longer, more deliberate multi-stop trip, we’ll go country by country instead.
The Local Number Problem
An eSIM handles data brilliantly, but it doesn’t give you a local phone number, which occasionally matters — a restaurant that wants to text you a confirmation, a taxi app that needs to send a verification code, or a hotel that prefers a local callback number. A few of the bigger providers now offer an add-on local number for exactly this reason, so it’s worth checking in the app before you go if you know you’ll need one. Otherwise, your home number keeps working fine for calls, texts, and two-factor codes from home — it’s only local businesses reaching you locally that occasionally need a workaround.
If Your eSIM Isn’t Working When You Land
This happens rarely, but here’s the order we troubleshoot in:
- Turn Airplane Mode on, wait ten seconds, then turn it off. This forces your phone to search for networks again.
- Double-check that your eSIM line — not your home line — is set as the active line for Cellular Data, and that data roaming is turned on for it.
- Confirm you’re not still inside a Wi-Fi-only zone, like some airport terminals, that might be masking the issue.
- Open the provider’s app and check for an APN (network) setting they want you to enter manually — most don’t require this, but a few countries do.
- Use the in-app chat support. In our experience this is fast, usually a real response within minutes, since getting you connected is their entire business.
- If all the above doesn’t work, be sure to turn off any VPN you have running. That may be interfering with the cellular connection. In general, if you’re on cellular data, there’s no need for a VPN. Reactivate it when you’re on the hotel’s or other public Wi-Fi.
eSIM Cost vs. Roaming: The General Picture
Exact prices shift by provider, country, and data amount, so check current rates in the app before buying rather than relying on a number in a blog post. What we can tell you from experience: a week of eSIM data in most popular destinations runs a fraction of what a phone carrier’s daily international roaming pass costs for the same week, and you’re not stuck with a single day’s worth of data that resets and charges you again at midnight. For any trip longer than a few days, the eSIM route has been the clear winner for us on cost alone — the convenience is just the bonus.
Frequently Asked Questions: Using an eSIM for Travel
What is an eSIM and how is it different from a regular SIM card?
An eSIM is a digital SIM card built into your phone rather than a physical chip you insert. You buy and activate a data plan through an app, using a QR code or one-tap install, instead of swapping a physical card at a kiosk.
Will I lose my regular phone number if I use an eSIM?
No. Your home number stays active on its own line for calls and texts. The eSIM runs as a second line, typically just for data, alongside it.
How do I know if my phone supports eSIM?
On iPhone, check Settings > General > About for a “Digital SIM” entry or EID number. On Android, check Settings > Network & Internet > SIMs for an option to add or download an eSIM. Most phones from 2018 or later support it, with some carrier-locked exceptions.
Should I install my eSIM before I leave home?
Yes — install it a few days ahead while you’re on home Wi-Fi, but don’t worry about burning your data early. Most providers only start the validity clock once you first connect to a network at your destination, not at install.
Which eSIM provider is best for a trip through several countries?
Look for a regional or global plan rather than single-country plans. Airalo in particular offers bundles covering multiple countries on one data allowance, so you’re not switching providers at every border.
What do I do if my eSIM doesn’t connect after I land?
Toggle Airplane Mode off and on to force a network search, confirm the eSIM line is set as active for Cellular Data with roaming turned on, and check the provider’s app for any required manual network settings. In-app chat support is usually fast if none of that works.
Is an eSIM cheaper than my phone carrier’s international roaming plan?
Usually, yes, especially for trips longer than a few days. Exact pricing varies by provider and destination, so check current rates in the app, but in our experience it’s consistently less than a carrier’s daily roaming pass for the same period.
For more of what’s on our phones when we travel, see our full guide to the best travel apps, and if you’re also locking down your data on public Wi-Fi, check our VPN guide.
