Emergency calls over VoIP, Wi-Fi calling and apps: what works and what does not
Short answer: use your phone's built-in dialler for emergencies. Carrier calls, including VoLTE and in most networks Wi-Fi calling, are designed to reach emergency services. Messaging and calling apps generally are not.
Why the type of call matters
Emergency services expect two things from a call: that it reaches the right local answering centre, and that they can find the caller. A mobile network can do both, because it knows which cell you are using and can obtain your handset's location. An app that sends voice over the internet between two accounts has no connection to the emergency system and no standard way to pass on your location.
The rules in the European Union
112 is the single emergency number across the EU and works alongside national numbers. The European Electronic Communications Code (Directive (EU) 2018/1972, Article 109) requires providers of "number-based interpersonal communications services" to give their users free access to emergency services, together with caller location information. That covers mobile and fixed telephone services, and internet-based services that let you call ordinary phone numbers.
It does not oblige "number-independent" services, the messaging and calling apps that connect accounts rather than phone numbers, to carry emergency calls. That is why the help pages of the major apps state that they cannot be used to call emergency numbers.
The Commission's 112 page explains how the number works, including alternatives for people who cannot make a voice call. EU rules also require operators to make caller location available; in practice many countries use Advanced Mobile Location (AML), in which the phone itself sends a precise GPS or Wi-Fi-based position to the emergency centre when an emergency call is made. Android and iOS both support it in countries where it has been deployed.
The rules in the United States
The FCC has required "interconnected VoIP" services, those that let users call and receive calls from the regular telephone network, to provide 911 service since 2005 (FCC 911 overview; consumer guide: VoIP and 911 service). Providers must obtain a registered location from the customer and explain any limitations of their 911 service. Under rules implementing the RAY BAUM'S Act, providers must also convey a "dispatchable location", meaning a street address plus details such as floor or room where feasible. Kari's Law requires multi-line telephone systems, such as office and hotel phone systems, to allow direct dialling of 911 without a prefix.
Wi-Fi calling and emergency calls
Wi-Fi calling runs through your operator's network, so on networks that support it an emergency call can be placed over Wi-Fi when there is no mobile coverage. How it behaves depends on the operator and the country:
- Many phones prefer the mobile network for emergency calls whenever any network is available, including another operator's network, which the phone is allowed to use for emergency calls even without your own coverage.
- Where the call does go over Wi-Fi, the operator may rely on the address you registered when you enabled the feature, plus any location the phone can provide. Keep that address up to date, especially if you move house.
- Some operators do not support emergency calls over Wi-Fi at all, or not from abroad. Your operator's Wi-Fi calling page should say.
Fixed VoIP lines at home and work
Many "landlines" are now VoIP, delivered through a router. They usually support emergency calls, but with two practical weaknesses:
- Power cuts. If the router has no power, the phone does not work. Some providers offer battery backup units; a charged mobile phone is the simplest fallback.
- Moving the equipment. If you take a VoIP adapter or desk phone to another address, emergency services may be sent to the registered address. Update it with your provider.
Calling apps: what to do instead
WhatsApp, Signal, FaceTime audio, Telegram and similar apps should be considered unable to reach emergency services. The same goes for many VoIP-to-phone credit services; check their terms, which commonly exclude emergency calls. If an app is your main way of calling, make sure the phone itself still has a SIM or eSIM, or at least that its dialler can place emergency calls: in many countries a phone without a SIM can still call 112, but national rules vary, and some networks no longer accept SIM-less emergency calls because of abuse.
Abroad
- 112 works throughout the EU and in a number of other countries; many phones also translate 112 or 911 to the local number automatically. Do not rely on that outside Europe: learn the local number.
- When you arrive in another EU country, your operator must send you information on reaching emergency services there (see EU roaming rules).
- If you use a data-only travel eSIM, your home SIM or the phone's emergency function is what places the call, not the eSIM's data connection.
Checklist
- Use the phone dialler, not an app, in an emergency.
- Keep the emergency address registered for Wi-Fi calling and home VoIP current.
- Know the local emergency number when travelling.
- Keep a charged mobile phone if your home line depends on a router.
- Check your operator's position on emergency calls over Wi-Fi.
For the difference between carrier calls and app calls, see Wi-Fi calling explained.