With WLAN calling, a technology has become established that ensures the seamless transition between classic telephony via mobile radio and WLAN. However, you have to be careful when abroad. Additional costs may be incurred for WLAN calling.
Most people know this from their own experience: The mobile phone connection in buildings is not always as good as one would like. This is especially true for underground car parks, shopping centres or similar large building complexes. This is one of the reasons why WLAN calling has established itself as a technology that ensures a seamless transition between classic telephony via mobile radio and WLAN.
If the smartphone is also connected to the internet via WLAN, it can automatically switch back and forth between the two technologies. The prerequisite is that the mobile device is logged in via LTE at the respective location. WLAN calling is now supported by a whole range of smartphones and mobile phone tariffs.
In addition to the advantages that you can make calls even in a dead zone and the connection quality is often better, you also benefit from a cost advantage outside the EU. If you call Germany from outside the EU, the call via WLAN is billed like a domestic call. So if you have a flat-rate phone plan anyway, you don't pay anything extra. Without a flat rate, it is at least much cheaper, because normal "world calls" often cost more than one euro per minute.
Nevertheless, it is important to be careful abroad, namely within the European Union. Because in the EU or in the European Economic Area with Liechtenstein, Norway and Iceland, the "Roam like at home" principle now applies. This means that you can use your phone as if you were at home, i.e. make phone calls, send text messages and surf the Internet without incurring additional charges.
However, this only applies to the mobile network, not to WLAN calling. Such calls are not covered by the EU Roaming Regulation, so providers are allowed to charge additional costs - and do. To avoid this, deactivate the WLAN calling option either with your provider or in the settings of your smartphone before leaving Switzerland. (Computerwoche)