How to use an eSIM in another country (step-by-step guide for first-time users)

An eSIM, or embedded SIM, is a digital SIM card built into the phone. It works like a SIM card, but there is no removable card to insert. Instead of opening a SIM tray and swapping a physical card, I installed an eSIM profile on my smartphone.

That was my first wrong assumption. I thought an eSIM card was another type of physical SIM. It is not. It is a virtual SIM stored on the device.

The second thing I learned was that most travel eSIMs are data-only. They usually do not include a local phone number for calls or SMS messages. That sounds limiting at first, but it made sense for international travel. I did not need a new number. I needed mobile internet for maps, WhatsApp, hotel bookings, train tickets, ride apps, and social media.

With my home SIM still active, I could still receive calls and SMS from home. For everyday communication, I used VoIP apps like WhatsApp, FaceTime, and Signal over the eSIM data connection. I use them daily anyway, so it didn't feel forced. Ten years ago, I would have felt limited by not having SMS in the prepaid plan - but now, with my family and friend chats all on WhatsApp, I haven't sent a single SMS in years.

1. Check your device’s compatibility and carrier lock status before buying. Your cell phone must support eSIM technology, and it must be carrier-unlocked to use a different provider’s eSIM.
   
   

2. Buy and install an eSIM before you fly. eSIM installations require internet access, so doing it at home on WiFi is much easier than trying to set it up at a foreign airport. I installed mine the day before; a friend traveling with me waited until we landed and spent ages fighting the weak airport WiFi to get it working. It eventually installed, but the frustration wasn't worth it.
   
   One thing worth checking before you install: when does your provider start counting the validity period? With WonderConnect, the plan only starts when you first connect to a network at your destination - so you can set everything up at home without burning days off your plan.
   
   

3. Keep your physical SIM active if you still need your home phone number, but turn off data roaming on that primary SIM.
   
   

4. Choose the right eSIM plan for your route. A local eSIM is enough for one country, a regional plan works better for several countries, and a global eSIM can make sense for a longer trip across multiple countries.
   
   

5. Estimate how much data you need before you buy. Most international eSIM plans are prepaid, which means you commit to a data amount up front instead of being billed for what you use. The right size depends on how long the trip is, how often you're online, and which apps you'll use most.
   
   

6. Check if your eSIM provider offers top-ups. Running out of data mid-trip is much less stressful when you can just buy more on your existing plan instead of installing a new eSIM from scratch. With WonderConnect, top-ups apply to the same eSIM profile, so you don't need to scan another QR code or redo the setup. You just keep using the eSIM you already have.

Before my first trip abroad with an eSIM, I checked whether my phone actually supported one. It's worth doing before you purchase any international data plan.

On iPhone, I went to Settings > General > About and looked for an EID. If a phone shows an EID or Digital SIM information, it usually supports eSIM.

On Android, the path varies. On many Samsung phones, it's Settings > Connections > SIM manager.

On Google Pixel, it's usually Settings > Network & internet > SIMs. Look for options like Add eSIM, Download SIM, or Add mobile plan.

Most modern iPhones - XS, XR, and newer - support eSIM, and so do most flagship Android devices, including recent Google Pixel and Samsung Galaxy models.

But eSIM support isn't the only requirement. The phone also needs to be carrier-unlocked... something I almost missed. If a phone is locked or has SIM restrictions from a mobile operator, it may not accept a travel eSIM from another provider.

If you bought your phone through a contract, check with the carrier one or two weeks before traveling. My phone came from a provider, so I just called and asked whether it was unlocked. It took less than two minutes - and you can't get a more reliable answer than from the carrier itself.

At first, I thought all international eSIM plans worked everywhere. They don't.

Plans usually fall into three types, and the right one depends on your route.

his was the part I overthought the most.

I asked myself: how much data do I actually need for a trip abroad?

The answer depends on the trip length and the apps. A long weekend with maps and messages needs much less data than two weeks of social media, video calls, and hotspot use.

For a short trip, 1 GB to 3 GB can be enough if I mostly use maps, messaging, email, and light browsing.

For a one- or two-week holiday, 5 GB to 10 GB is usually safer, especially if I use Instagram, TikTok, Google Maps, translation apps, restaurant apps, and cloud-based travel documents.

For an extended time abroad, 15 GB, 30 GB, or more data may make sense. Video calls, HD streaming, app updates, photo backups, and hotspot use can use a lot of cell data.

I also learned to overestimate slightly. I once forgot that cloud photo sync was turned on. A few videos started uploading over mobile data, and my data usage went up faster than expected.

WonderConnect has a Travel Data Calculator, which helped me think in normal travel activities instead of gigabytes. I could estimate data based on maps, social media, video calls, streaming, and general phone use.

Most international eSIM data plans are prepaid, so there is no bill shock. If I need more data, I can top up online instead of paying automatic roaming fees from my home carrier.

Installation needs internet access, and airport Wi-Fi is often weak, crowded, locked behind a login page, or just not working. I now install the travel eSIM a day or two before the flight. That leaves time to confirm the profile appears correctly in my network settings without rushing through it in a noisy terminal.

The buying part is straightforward. In the WonderConnect app or website, search your destination, pick the data amount, confirm device compatibility at checkout, and pay. The eSIM details arrive by email and in your WonderConnect account.

From there, there are three ways to install the eSIM. Use whichever your phone supports.

In-app installation (easiest, when available). This is a newer option - older iOS versions didn't support it. Open the WonderConnect app, find your order, and tap "Install eSIM." The phone jumps straight to the right Settings screen. No QR code, no copying, no manual entry.

QR code (the most common method). Open your confirmation email on a separate screen - laptop, tablet, or a printed copy - so your phone's camera can scan the code. Then on the phone:

iPhone: Settings > Cellular > Add eSIM > Use QR Code

Android (Pixel): Settings > Network & internet > SIMs > + Add eSIM

Android (Samsung): Settings > Connections > SIM manager > + Add eSIM

Point the camera at the QR code and wait for the profile to load.

Manual entry (use it if the QR code won't scan). Your WonderConnect email lists three pieces of information: an SM-DP+ address, an activation code, and QR code. Follow the same Settings path as above, choose "Enter Details Manually" instead of scanning, and paste each value into its matching field:

• On iPhone: SM-DP+ address → SM-DP+ Address field, activation code → Activation Code field.

• On Android: paste only the activation code into the Activation Code field. Android handles the SM-DP+ part on its own.

The whole installation usually takes a couple of minutes. Don't interrupt it, wait until the new eSIM appears in your network settings. By default it might be labeled "Travel," "Secondary," "Mobile Data," or something provider-specific like "eSIM-GO."

You can rename it during installation or any time afterward. I always rename mine "Travel – destination name" so I can tell which line is which at a glance.

This was the part I expected to be technical, but it really came down to flipping the right three switches in Settings.

After landing, I opened my phone's network settings and did three things in order:

1. Turned on the travel eSIM line.

2. Set the travel eSIM as the line for cellular data. That's the step that tells the phone to use the eSIM for internet instead of the home SIM.

3. Enabled Data Roaming for the travel eSIM - and only for the travel eSIM, not the home SIM.

That third step is the one that trips first-time users up. I thought data roaming should always be off when traveling and that's true for the home SIM, which would otherwise rack up charges from your home operator. But a travel eSIM connects through a roaming partner network in the destination country, so it needs roaming enabled to work.

Within a minute or two, my phone picked up a local carrier - its name appeared in the status bar - and mobile data started working. I opened Maps, sent a WhatsApp message, and booked a ride without ever looking for a local SIM shop.

Modern smartphones support dual-SIM, which means a physical SIM and an eSIM can run side by side. Most modern phones can also run two eSIMs at the same time - a home-country eSIM for calls and SMS, plus a travel eSIM for mobile data. iPhones from the 13 onward and most recent flagship Android phones support this.

That mattered to me because I didn't want to lose access to my regular phone number. I kept my primary SIM active for receiving calls and text messages from home, and used the eSIM strictly for data.

Labeling each line in Settings really helps - and it matters even more when both lines are eSIMs. With a physical SIM and an eSIM, the phone usually shows them as two distinct line types, so they're easy to tell apart. With two eSIMs, both lines just appear as "eSIM" until you rename them - which makes it easy to toggle data roaming on the wrong one. Pick names that make it obvious which is which: I use "Home SIM" and "Travel - country name." Once they're labeled, you'll see at a glance which line handles calls and SMS and which handles mobile data.

I also assumed that if an eSIM ran out, I'd need to install a new one from scratch. That wasn't the case - I just needed to buy extra data for the same eSIM.

My first eSIM trip went smoothly, but I still learned a few basic checks.

If the eSIM doesn't connect right away, I run through three quick checks: is the travel eSIM turned on, is it selected for cellular data, and is data roaming enabled on it (and not on the home SIM). If all three look right, I toggle airplane mode on and off, and restart the phone if that doesn't help.

If the signal is weak, I move somewhere more open. Coverage depends on the local network, and it tends to be patchy in remote places, underground stations, ferries, mountains, or older buildings. If you're heading somewhere with uncertain coverage, you can check which local carriers your eSIM connects to before you buy - most providers list this in the plan details.

If the eSIM still struggles to lock onto a signal, I temporarily turn off the home SIM line. That often helps the eSIM grab a stronger connection without the device juggling both. Once it's stable, I switch the home SIM back on.

If nothing works, I contact support with the device model, destination country, eSIM details, and screenshots of the mobile network settings. That's much faster than just saying "my eSIM doesn't work."

• I thought an eSIM would replace my traditional SIM. It didn't. I could use an eSIM and keep my physical SIM active.

• I thought I'd get a new local phone number. I didn't, because most travel eSIMs provide data-only service and don't include phone calls or SMS.

• I thought eSIM activation would be difficult. The only time it felt difficult was before I understood the difference between installation and activation. Installation adds the eSIM profile to the phone. Activation for travel usually means turning it on, selecting it for cellular data, and enabling data roaming for that line after arrival.

• I thought data roaming always had to be off. Now I know it should be off on the home SIM, but on for the travel eSIM when required.

• I thought I needed to buy a local SIM at the airport to get good coverage. In practice, the travel eSIM connected to a local carrier network without me visiting a shop.

• I thought one eSIM worked everywhere. It depends on the plan. A local plan may cover one country only. A regional or international plan may cover multiple countries.