To use calling and messaging apps like WhatsApp, Messenger, or FaceTime while traveling, you generally don't need a local phone number. As long as you have a working data connection (internet), these apps handle your chats, voice calls, and video calls. In other words, once your phone is online abroad, you can stay in touch with family and friends back home using the same apps you always use. This guide breaks down how it works, what to set up before you go, and the points where people often get stuck.
- With a data connection, app-based calls and chats work abroad just like at home
- No local phone number needed — you connect account-to-account
- Dialing phone numbers and standard SMS won't work, but app calls (WhatsApp, etc.) will
- Video calls use a lot of data (hundreds of MB and up), so leave yourself room
- If you rely on SMS verification, keep a backup such as your home number
One important point first. A Bloomy eSIM is data-only by design. The "in-app calls and messages" in apps like WhatsApp work over data, but dialing an actual phone number or sending a standard SMS to a mobile number may require a separate solution. Knowing this upfront saves you confusion once you're abroad.
The short answer: with data, your usual apps just work
Here's the bottom line: apps like WhatsApp, Messenger, Instagram messaging, and FaceTime (on supported devices) work abroad the same way they do at home, as long as you have a data connection. App calls run over the internet, so they connect you "account-to-account" rather than through a phone number.
All you really need is a way to get your phone online 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 starts, and you're connected right away. You can check destinations and data options on our eSIM comparison page. If you'd like to weigh all the ways to stay connected abroad, see our guide to travel connectivity options.
Why do calling apps work without a phone number?
Calls in apps like WhatsApp don't use a carrier's "voice line" — they use your internet connection (data). This is commonly known as VoIP (internet calling). Because your voice is turned into data and sent over the internet, you don't need a local phone number to reach the other person.
So even without a local 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, calling an actual phone number or sending an SMS to a number requires voice-line and SMS functionality. A data-only eSIM doesn't cover those, so if you need them, consider a separate option (more below). For more on numbers and SMS, see our phone number & SMS guides.
Quick reference: popular apps and what works on data
Here's what you can do on a data connection with some of the most common apps (as of June 2026 — each app's features may change).
| App | Messaging | Voice & video calls | Notes |
|---|---|---|---|
| ✓ | ✓ | A phone number is required to register. Once registered, it works over data | |
| Messenger | ✓ | ✓ | Log in with your account to use it |
| Telegram | ✓ | ✓ | A number is usually needed at sign-up; daily use runs over data |
| FaceTime / iMessage | ✓ (iMessage) | ✓ | Apple devices only. Depends on device and Apple ID settings |
The key point: many apps may use a phone number for the initial sign-up or verification, but once you're registered, day-to-day messaging runs entirely on data. Completing any number verification before you travel gives you peace of mind.
Getting ready to use them abroad (before you leave)
A little preparation before departure keeps you from scrambling once you arrive. The steps are simple.
- Update your apps and confirm you're logged in: Make sure you can sign in to WhatsApp and others before you go. For apps that need number verification, take care of it while you still have your usual number.
- Check that the people you want to reach are on the same app: Confirm in advance that they can use the same app. Asking family to install WhatsApp before you leave saves trouble later.
- Set up your connection for abroad: If your phone supports eSIM, you can install it before departure. Check whether your device is compatible on our eSIM-compatible devices page.
- Pick a plan that fits your destination, trip length, and data needs: If you're mostly messaging, you won't need much data — but if you'll be on a lot of video calls, give yourself some headroom. Use the comparison page to choose by country, data amount, and number of days.
For the specifics of installing an eSIM and scanning the QR code, see our setup guide.
How much data do calling apps use? Rough estimates
Worried that calling apps will burn through your data fast? Here are general estimates. Actual usage varies by app, conditions, and video quality, but this gives you a rough idea (approximate, as of June 2026).
| Usage | Approx. 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 mainly send messages, data use is barely noticeable — but video calls consume a lot of data. If you're planning long video calls, a plan with plenty of data, or an option that lets you use more, is the safer choice. If you're unsure how much data to get, weigh it alongside trip length on the comparison page.
Good to know: what a data-only eSIM can and can't do
To be upfront: because a Bloomy eSIM is data-only by design, there are things it can and can't do.
What works over data
- In-app messaging, voice 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
- "Voice calls" dialed directly to someone's phone number
- Sending and receiving standard "SMS" to a phone number (such as SMS verification codes from banks or certain services)
In particular, SMS verification is sometimes used to log in to banks, brokerages, and some web services. If you rely on these, it's worth also checking on a way to keep an active number or a number-capable option. Since SMS verification and number retention depend on each service's policies, confirm the latest details with each provider directly. We've gathered more in our phone number & SMS guides.
Note that even if you choose an unlimited-type plan, it doesn't mean completely unrestricted use. 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 at the time of purchase.
What to do when you can't connect or calls keep dropping
If an app won't open or a call keeps dropping while you're abroad, don't panic — work through these in order.
- Check that data is on: Confirm the eSIM line is activated and mobile data is turned on. An eSIM you installed before the trip needs to be "switched on" once you arrive.
- Make sure you're not in airplane mode or out of coverage: Toggling airplane mode off and on once can sometimes help.
- Move to a spot with a better signal: Basements and the interiors of large buildings tend to have weak signal. Video calls especially need a stable connection.
- Switch between Wi-Fi and data: An unstable Wi-Fi connection can actually cause drops. Try turning Wi-Fi off and using your eSIM data instead.
- Restart the app and your device: If nothing else works, restart your phone.
For detailed setup steps and connection checks, see our troubleshooting guide.
How Bloomy can help (setting up your way to stay in touch)
Bloomy eSIM is designed so that first-time eSIM users abroad never feel lost. We offer a comparison page where you choose by destination, data amount, and number of days, a device compatibility check to see if your phone is supported, and a setup guide that walks through installation. After purchase, you can check your remaining data and QR code from My Account.
"I want to message family every day," or "I need to stay reachable for work while I'm away" — for connection-focused use like this, getting your data sorted 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 below, we answer common questions about numbers, SMS, and data usage. For more detailed questions, see our FAQ page.
