Fresim

WiFi Calling with eSIM: eSIM & Mobile Connectivity Explained

WiFi calling with eSIM lets you make calls and send texts over WiFi abroad using your home number. Learn how VoWiFi works, what you need and how to set it up.

Updated 16 October 2026

In one sentence

WiFi calling lets your phone make and receive normal phone calls and texts over a WiFi connection instead of a mobile tower, so you can keep using your home number abroad while a travel eSIM handles your mobile data.

In detail

WiFi calling (also called VoWiFi, short for Voice over WiFi) sends your regular calls and SMS texts through the internet rather than through the cellular network. Your contacts still dial your usual number and your phone rings as normal. It is a feature of your home carrier's phone line, so it only works if your carrier supports it and you have switched it on in your phone settings. Most modern iPhones and Android phones support it, and many phones let you run two lines at once, such as your home SIM plus a travel eSIM. A travel eSIM is usually a data plan, so the usual setup is simple: the travel eSIM provides mobile data and your home line stays on for WiFi calling.

How it works

When WiFi calling is on, your phone sets up a secure, encrypted tunnel over the WiFi network back to your home carrier's phone system. Calls and texts travel through that tunnel, so the carrier treats you as reachable on your normal number, even from another country. Your phone switches between WiFi and cellular automatically, and some phones can hand a call over between the two.

Why travellers should care

WiFi calling is how you can still receive a bank verification text, a call from family or a call from your doctor on your usual number while you are overseas, without turning on expensive roaming. Pair it with a travel eSIM for data, and you can use maps, messaging and video calls the moment you land. Charges for calls made over WiFi vary by carrier and plan, so check what your carrier charges for calls to local and international numbers before you go.

Related terms

  • VoWiFi
  • WhatsApp calls
  • FaceTime
  • home number abroad

Example

Priya, a travel blogger from Melbourne, lands in Lisbon for a two-week trip. On the flight she checks that WiFi calling is switched on for her home line. At the airport she taps Install on iPhone in her eSIM delivery email (or scans the QR code from her laptop screen) and picks her travel eSIM for mobile data. She sets her home line to off for data and keeps it on for calls and texts. At her hotel, her bank's verification text arrives on her usual number over WiFi, and her mum's phone call rings through as normal. Meanwhile, Google Maps and Instagram run on the travel eSIM's data while she walks around the city.

Key takeaway

Use a travel eSIM for cheap mobile data and keep WiFi calling switched on for your home line, so people can still reach you on your usual number abroad.

Frequently asked questions

Does WiFi calling work with an eSIM?

Yes, if your carrier supports WiFi calling on the line you are using. WiFi calling is a feature of a phone line, so it works on a carrier eSIM or a physical SIM. Most travel eSIMs are data-only plans, so they are used for internet access, while your home line handles WiFi calling.

Can I use WiFi calling abroad without roaming charges?

Often you can avoid data roaming charges because calls travel over WiFi, but carriers differ on what they bill for calls and texts. Some treat WiFi calls from overseas like calls made at home, while others apply international rates. Check your carrier's WiFi calling terms before you travel.

How do I turn on WiFi calling on my iPhone or Android?

On iPhone, go to Settings, then Mobile Service (or Cellular), choose your line and switch on WiFi Calling. On most Android phones, open Settings, then Network and Internet or Connections, and look for WiFi Calling. Menu names differ between brands, and your carrier may ask you to confirm an emergency address.

Can I keep my home number abroad and use a travel eSIM at the same time?

Yes, on a dual-SIM phone. Keep your home line active for calls and texts with WiFi calling on, and install a travel eSIM for data. Fresim eSIMs arrive by email with a one-tap install button (Install on iPhone for iOS 17.4+ or Install on Android for Android 10+), plus a QR code if you want to install from another screen.

Is WiFi calling better than WhatsApp or FaceTime calls?

They do different jobs. WhatsApp and FaceTime calls only reach people who use the same app, while WiFi calling connects you to any phone number and receives calls to your normal number. For friends and family on those apps, app calls are great. For banks, businesses and anyone who only has your number, WiFi calling is the better fit.

Where you'll use this

More esim glossary

Sources

  • Apple Support — Make a call with Wi-Fi Calling on iPhone
  • Google Android Help — Make calls over Wi-Fi on Android phones
  • GSMA — Voice over WiFi (VoWiFi) and WiFi Calling Industry Guidelines
  • 3GPP — IMS Services over Untrusted Non-3GPP Access Specifications