Understanding Data-only eSIM

Data-only eSIMs are a popular choice for travelers because they offer flexible internet access without the need for a physical SIM card. But can eSIMs make calls? This article will give you the answer, as well as instructions on how to use eSIMs for communication while traveling.

What is a data-only eSIM? Can it make calls?

Source: Pexels

Simply put, a data-only eSIM is a type of SIM card that only provides mobile data for you to access the internet, does not come with a phone number and does not support regular calls or SMS.

The main difference between a data-only eSIM and a regular eSIM lies in the communication function. While a regular eSIM (usually issued by a domestic carrier) has its own phone number and fully supports calling, texting and internet access, a data-only eSIM is designed to be optimized for network access needs, often used for international travel or short-term needs.

However, you can still communicate normally through the application, as long as there is an internet connection. These are voice over internet (VoIP) applications such as WhatsApp, Viber, Zalo, Skype... that support both audio and video calls. In fact, many people only need to use a data-only eSIM to stay in touch during their trips without needing a physical SIM or main phone number.

How to make calls with a data-only eSIM while traveling

Here, Aviro will guide you through some common ways to make calls when using a data-only eSIM.

1. Call via OTT messaging app

Source: Pexels

Popular messaging apps like WhatsApp, Zalo, Facebook Messenger, Telegram, Viber, LINE all support voice and video calls over the internet. As long as you and the recipient have the app installed, connecting will be easy and completely free, no matter which country you are in.

Advantage:

• Familiar interface, easy to use

• No local phone number required

• Supports both video calling and sending files and photos

Note: Some apps (like WhatsApp) require an initial phone number verification , so you should activate and log in before switching to a data-only eSIM.

2. Use VoIP application to call the phone number

If you need to call a landline or mobile phone, you can use VoIP (Voice over IP) services such as:

• Skype : Allows you to call any phone number in the world at low cost. You can buy a plan by the minute or add money to your account.

• Google Voice (available in select countries only): Lets you make and receive calls using your own Google number.

• TextNow, Talkatone : Gives you a virtual phone number to make calls, mainly supported in the US and Canada.

Advantage:

• Call any phone number, even people who don't use the app.

• Much cheaper than calling with international roaming.

Note: Some services require you to set up an account in a specific country (e.g. Google Voice in the US). You should check the terms and conditions first.

3. Tips for making effective calls when using data-only eSIM

In addition to knowing the apps, you can apply the following tips to help make calling and texting with eSIM smoother:

• Prioritize stable Wi-Fi

• Use 4G/5G network instead of 3G for better sound quality

• Turn off bandwidth-hungry apps like YouTube, Netflix, Facebook, TikTok, Spotify, or apps that download data in the background

• Consider updating your phone software and calling apps regularly to avoid bugs.

• Use headphones with quality mic for clear sound and noise reduction

• Make sure your phone battery has enough capacity to maintain stable performance

Instructions for activating and using data-only eSIM

Source: Canva

Before purchasing an eSIM, you need to check whether your device supports eSIM or not .

You can purchase a travel eSIM from providers like Aviro. After payment, a QR code or activation code will be sent via email within minutes.

Next, Aviro will guide you through using your primary phone number with a data-only eSIM while traveling:

1. Keep the main SIM always on (do not remove or turn off)

Even if you're using an eSIM to access the internet, make sure your physical SIM (or primary eSIM) – the one that contains your phone number – is still enabled. If you remove the SIM or turn it off in settings, you won't be able to make/receive calls and receive SMS using that number.

2. Turn off “Data Roaming” for primary SIM

Go to Settings > Cellular (or Mobile Networks) on your phone and turn off "Data Roaming" for your primary SIM. This prevents your SIM from automatically using international data and incurring high charges.

In addition, to make sure you are not using a roaming package, proactively call the operator or check your account to make sure you are not activated by default.

3. Turn on data-only eSIM and select it as primary mobile data source

To use the internet while abroad and avoid roaming charges , as soon as you arrive, turn on your travel eSIM and make sure that in Settings > Mobile data, you have selected eSIM as your default mobile data source. Specifically:

• For iPhone: turn on Data Roaming for eSIM.

• For Android: select eSIM as primary SIM for mobile data.

4. Configure primary SIM for calls and messages

To ensure you can still receive/send messages or calls using your original phone number, do the following:

• On iPhone : Go to Settings > Cellular > Default Line > iMessage & FaceTime, select primary SIM.

• On Android : Go to Settings > Mobile Network > Calls & Messages, select primary SIM.

Note: You must enable data roaming on your primary SIM in Vietnam, before going abroad.

5. Notes on international calls and SMS

Even if you use eSIM for data, calls or messages made with your main SIM abroad will still be charged internationally according to your carrier's rates. It's best to prioritize calling via apps (like WhatsApp, Zalo, Viber, Messenger...) to save costs!

Data-only eSIMs are a smart way to stay connected while traveling internationally, avoid roaming charges, and still make calls over the internet using popular apps. With the right setup, you can have a seamless experience throughout your trip. If you don’t have a data-only eSIM yet, contact Aviro today via email Sales.VN@avironetwork.com or live chat on the website!