How Does a Travel eSIM Work? Everything You Need to Know Before Your Trip
2026 | The Dufresnes
A travel eSIM is a digital SIM card built into your phone that lets you access mobile data in another country without swapping out a physical SIM card. You buy a plan online, receive a QR code by email, scan it to install the eSIM, and when you land at your destination you switch your data over and you're connected — no airport queues, no SIM card shops, no paperwork.
After 9 years of full-time travel across Costa Rica, Central America, Southeast Asia, and Hong Kong, eSIMs have become one of the most important parts of how we travel as a family. Here's everything you need to know about how they work — and how to get the most out of one.
What Is an eSIM?
An eSIM (embedded SIM) is a SIM card that lives inside your phone permanently — it's soldered directly onto the motherboard rather than sitting in a tray. Instead of physically inserting a SIM card, you install a travel plan onto it digitally by scanning a QR code.
The concept is the same as a regular SIM card — it connects your phone to a mobile network and gives you data — but the delivery is entirely digital. No plastic card. No tiny tray. No losing your home SIM in a guesthouse somewhere in Southeast Asia.
How Does a Travel eSIM Work Step by Step?
Step 1: Buy your plan online Choose a travel eSIM provider, select your destination and the number of days you need, and complete the purchase. The whole process takes a few minutes.
Step 2: Receive your QR code by email Immediately after purchasing, you'll receive a QR code to your email address. This is your eSIM — it contains all the information needed to connect your phone to the provider's network at your destination.
Step 3: Install the eSIM on your phone Go to your phone's Settings, find the SIM or Mobile Data section, and select "Add eSIM." Scan the QR code using your camera — you need to be on WiFi to do this. The eSIM installs in seconds.
Step 4: Set it up correctly Once installed, you'll see the eSIM listed as a second line on your phone. Set it as your data line. Leave your home SIM active for calls and texts. Turn on Data Roaming.
Step 5: Arrive at your destination and switch it on When you land, switch your active data line to the eSIM. Your phone connects to a local carrier tower automatically. You're online.
That's it. The whole process from purchase to installation takes under 10 minutes, and most of it happens at home before you even pack a bag.
Can I Use My Regular SIM and an eSIM at the Same Time?
Yes — and this is one of the biggest advantages of travel eSIMs.
Most modern smartphones support dual SIM functionality, meaning they can run two SIM cards simultaneously. Your physical home SIM handles calls and texts, keeping your regular phone number active, while your travel eSIM handles all data.
In practice this means:
- Your phone number stays the same — calls and texts come through normally
- WhatsApp stays connected to your regular number
- You use the travel eSIM for all data — Maps, internet, apps, uploads
- You don't need to tell anyone your number has changed, because it hasn't
This is fundamentally different from buying a local SIM card abroad, which typically replaces your home SIM entirely and gives you a new number your contacts don't have.
When Should I Activate My Travel eSIM?
Install it before you leave home. Activate it when you land.
Installing and activating are two different things:
Installing means scanning the QR code and adding the eSIM to your phone. Do this at home on WiFi before you travel. You need an internet connection to scan the QR code — don't leave this until you're at the airport or already abroad.
Activating means switching your data line to the eSIM. Do this when you arrive at your destination — as you come through the airport or cross the border. Some eSIM plans start counting days from activation, others from first connection — check your specific plan's terms.
Our routine: install at home a day or two before travel, activate as soon as we land.
Do I Need Internet to Install an eSIM?
Yes — you need a WiFi connection to scan the QR code and install the eSIM.
This is the most common mistake first-time eSIM users make: waiting until they've already arrived at their destination to install, then realising they need internet access to do it. If you're relying on the eSIM for your internet access, you're in a catch-22.
The solution is simple: install at home on your own WiFi before you travel. It takes less than two minutes and eliminates any airport stress.
Which Phones Support eSIM?
Most modern smartphones support eSIM. Here's a quick guide:
Apple iPhone: XS and later (all models from 2018 onwards). iPhone 14 and later in the US are eSIM-only with no physical SIM tray.
Samsung Galaxy: S20 and later, Z Fold and Z Flip series, Note 20 and later.
Google Pixel: Pixel 3 and later.
Other Android: Most flagship Android phones from 2020 onwards. Check your phone settings under SIM & Network, or search your model name plus "eSIM compatible."
One critical requirement beyond compatibility: your phone must be carrier unlocked. If you purchased your phone directly from a carrier on a contract, it may be locked and unable to use third-party eSIMs. Contact your carrier to request an unlock — most do this for free once your contract is fulfilled.
What's the Difference Between a Travel eSIM and a Local SIM Card?
| Travel eSIM | Local SIM Card | |
|---|---|---|
| Setup | Digital — install via QR code at home | Physical — buy in store at destination |
| Your home number | Stays active on your home SIM | Goes inactive while local SIM is in use |
| Multiple countries | Regional plans cover many countries | Need a new SIM for each country |
| Time to set up | 5 minutes at home | 20–60 minutes at destination |
| Passport required | No | Often yes |
| Works before arrival | Yes | No |
| Data | Unlimited with Holafly | Usually capped in GB |
For short trips, multi-country itineraries, or anyone who values convenience, travel eSIMs win on almost every point. For a long single-country stay where you have time to find a local store, a local SIM can occasionally be cheaper — but it comes with friction at every border.
Why We Use Holafly
After trying multiple options over 9 years of travel, Holafly is what we use on every trip. The key reason: unlimited data. Most travel eSIM providers sell data in gigabytes. Holafly sells by the day with no GB cap — for a family uploading YouTube content, running video calls, and navigating constantly, that's the only model that makes practical sense.
Holafly also includes Always On with every product — 1GB of automatic monthly backup data that activates when your main plan ends, at no extra charge.
Use code THEDUFRESNES at checkout:
- 5% off traditional eSIM plans
- 10% off monthly Holafly Plans
- 32% total off annual Holafly Plans
FAQ
Can I have more than one eSIM on my phone? Most phones support multiple eSIM profiles but can only use one at a time for data. You can store several and switch between them.
Does a travel eSIM work for calls? Travel eSIMs are data-only. For calls, your home SIM stays active. Apps like WhatsApp, FaceTime, and Google Meet all work over eSIM data with no issues.
What if my eSIM doesn't connect when I arrive? Toggle Airplane Mode off and on. Check that Data Roaming is switched on and the eSIM is set as your active data line. Holafly's 24/7 live chat support resolves most issues in minutes.
Will my eSIM work on a plane? In Airplane Mode all connections are disabled. Once you land and turn Airplane Mode off, your eSIM reconnects automatically.
We are Official Holafly Ambassadors. All opinions are based on 4+ years of personal use across 9 years of full-time family travel.