To use calling and messaging apps like WhatsApp, Facebook Messenger, or FaceTime while traveling, you generally don't need a local phone number. As long as your phone has a data connection (internet), these apps let you chat, make voice calls, and make video calls. In other words, once you have a way to get your phone online abroad, you can stay in touch with family and friends back home using the same apps you always use. This article breaks down how it works, what to prepare, and the points people tend to trip over.
One important note first. A Bloomy eSIM is generally data-only. The “in-app calls and messages” in apps like WhatsApp work over data, but dialing an actual phone number, or sending and receiving SMS (text messages) to a mobile number, may require a separate solution. Keeping this in mind from the start will save you confusion once you arrive.
The short answer: with a data connection, your usual apps just work
To get straight to the point: apps like WhatsApp, Messenger, Instagram messaging, and FaceTime (on supported devices) work the same way abroad as they do at home, as long as you have a data connection. App calls travel over the internet, so they connect you “account to account” rather than through someone's phone number.
All you need is a way to get your phone online while you're abroad. One option is an eSIM. Install the eSIM on your phone before you leave, then simply activate the line after you arrive—your data connection starts and you can get in touch right away. You can check destinations and data options on our eSIM comparison page. If you'd like to weigh up your connectivity options more broadly, see our guide comparing ways to stay connected abroad.
Why do calling apps work without a phone number?
Calls in apps like WhatsApp don't use a carrier's “voice line”—they use the internet (data connection). This is commonly known as “internet calling” or VoIP. Because your voice is turned into data and sent over the internet, you don't need a local phone number to connect with the other person.
That means even without a local phone number abroad, a data connection alone lets you:
- Exchange messages on WhatsApp, Messenger, and similar apps
- Make voice and video calls with anyone using the same app
- Share photos and locations, and chat in groups
On the other hand, placing a regular “phone call” to someone's actual phone number, or sending an “SMS” to a number, requires a voice line and SMS capability. A data-only eSIM doesn't cover these, so if you need them, consider a separate solution (more below). If you'd like to understand numbers and SMS in more detail, we've gathered it in our guide to phone numbers and SMS.
Quick reference: popular apps and what works over data
Here's a quick look at what you can do over a data connection with some common apps (as of June 2026; each app's specs may change).
| App | Messaging | Voice / video calls | Notes |
|---|---|---|---|
| Yes | Yes | A phone number is needed to register. Once registered, it runs on data | |
| Messenger | Yes | Yes | Sign in with your account to use it |
| Telegram | Yes | Yes | Number used at sign-up; everyday use runs on data |
| FaceTime | Yes (iMessage) | Yes | Between Apple devices. Depends on device and Apple ID settings |
The key thing to remember: many apps may use a phone number for the initial sign-up or verification, but once that's done, day-to-day contact runs entirely on data. Completing any number verification before you leave makes for a smoother trip.
Getting ready to use apps abroad (do this before you go)
A little preparation before departure saves a lot of stress later. The steps are simple.
- Update your apps and confirm you're signed in: Make sure you can sign in to WhatsApp and any other apps while you're still at home. For apps that require number verification, complete it before you leave.
- Check that the people you want to reach are “connected” on the app: Confirm in advance that they use the same app. For example, ask family to install WhatsApp before you go.
- Set up your connectivity: If you have an eSIM-compatible phone, you can install the eSIM before departure. Check whether your device is supported on our eSIM-compatible devices page.
- Choose a plan that fits your destination, length of stay, and data needs: If you mainly need to stay in touch, you won't need a huge amount of data—but if you make a lot of video calls, give yourself some room. The comparison page lets you choose by country, data, and number of days.
For the specifics—installing an eSIM, scanning a QR code, and so on—see our setup guide.
How much data do calling apps use? Rough guidelines
Worried that using calling apps a lot will burn through your data? These are general guidelines only and will vary with your environment, the app, and the video quality, but here's a rough picture (approximate, as of June 2026).
| How you use it | Rough amount per hour |
|---|---|
| Mostly text chat | Very little (a few MB) |
| Voice calls | Roughly tens of MB |
| Video calls | Roughly hundreds of MB and up |
If you mostly send messages, data usage isn't much of a concern—but keep in mind that video calls use significantly more data. If you're planning long video calls, a plan with more generous data is the safer choice. If you're unsure how much data to pick, weigh it alongside the number of days on the comparison page.
Good to know: what a data-only eSIM can and can't do
Let's be straightforward. Because a Bloomy eSIM is generally data-only, there are some things it can do and some it can't.
What works over data
- In-app messages, calls, and video calls on WhatsApp, Messenger, and similar apps
- Maps, search, social media, email, and the internet in general
What needs a separate solution
- A regular “voice call” dialed directly to someone's phone number
- Sending or receiving “SMS” to a phone number (such as SMS verification codes from banks or some services)
In particular, SMS verification is sometimes used to log in to banks, brokerages, and certain web services. If you rely on these, it's worth also checking how to keep your existing number active, or a solution that includes a number. Because SMS verification and number retention depend on each service's rules, always confirm the latest details with the provider directly. We cover this in our guide to phone numbers and SMS.
Also note that even if you choose an unlimited-type plan, it doesn't mean usage is entirely without limits. A fair use policy, speed management after a certain amount of usage, or tethering conditions may apply, and connection speeds also depend on the local network, area, and congestion. Please check the latest terms shown before you buy.
What to do when you can't connect or calls keep dropping
If an app won't open or a call keeps cutting out while you're abroad, don't panic—work through these checks in order.
- Confirm data is on: Check that the eSIM line is activated and mobile data is switched on. An eSIM you installed before departure needs to be “turned on” once you arrive to start using it.
- Check for airplane mode or no signal: Toggling airplane mode on and off once sometimes helps.
- Move to an area with a better signal: Basements and the interiors of buildings tend to have weak signal. Video calls in particular need a stable connection.
- Switch between Wi-Fi and data: An unstable Wi-Fi connection can actually cause drops. Turn Wi-Fi off and try the eSIM's data connection instead.
- Restart the app and the device: If it still won't work, restart your phone.
For more detailed settings and connection checks, see our troubleshooting guide.
How Bloomy helps (an easy way to set up staying in touch)
Bloomy eSIM is built so that first-time eSIM users don't get lost. We offer a comparison page where you can choose by destination, data, and length of stay, a device compatibility check to confirm your phone is supported, and a setup guide that walks you through installation. After purchase, you can check your remaining data and QR code in My Account.
“I want to message family every day,” “I need to stay reachable for work while I'm away”—if staying in touch is your main goal, getting a data connection in place clears up most of the worry. Start by checking the plans for your destination and whether your device is supported.
Frequently Asked Questions (FAQ)
In the FAQ that follows, we answer common questions about numbers, SMS, data usage, and more. For further questions, see our FAQ page.
