Which are the apps for cheap international calls?

Reducing your bill using data to call abroad

With so many companies offering free calling services for iPhone users it's quite easy to get confused. Some like Skype and Viber should already be household names for any smartphone users really. The question is, how do they fare against the competition?

Voice and video call services come in every flavour. While some are completely free, others include paid-for content in the form of international minutes as in-app-purchases. These also range in quality, regardless of how good your Wi-Fi or cellular network connection is. And of course, they're more or less efficient using data, meaning the right choice of app can save you some money in your cellular network data plan.

Skype

Being one of the first to support voice, video conference and chats on PCs, Skype is the reference voice over internet (VoIP) services. iPhone users have seen the early efforts to bring those free calls to the platform slowly. Nowadays with version 4.2 users can enjoy certain level of backgrounding — allowing your account to be online at any time and receive calls normally with a notification.

The positive points are the video support, option to call landline and mobile numbers using Skype credit as well as traditional SMS.

FaceTime

Apple's own videoconferencing solution comes already installed on iOS devices and new Macs. Perhaps for having to login using your Apple ID, the adoption of this perfectly good service has been very very slow. This has been addressed recently by allowing people to associate their mobile numbers, but this option not so obvious unless you tinker with the settings.

FaceTime's strong points are the best video quality on mobiles out there and not having to login or activate the app to use it. As long as you have network connection you'll be able to receive a call, which saves a lot of "preparation time" you get with other services.

Viber

If WhatsApp is the king of the free SMS, Viber has enjoyed similar hype for free calls. Integrating with your contact list on your iPhone, Viber only requires you to sign up using your mobile number, no username or account password required.

Viber's killer feature is showing you which contacts have installed the app already, saving you the effort to exchange usernames, invitations or emails to get it working.

Line

One recent discovery that is winning a young following around the world. Thanks to its refined user interface and quirky features such as emoji, chat stickers and mini homepage with status updates, Line is grabbing attention from hardcore WhatsApp users. As part of its offering, the service by Naver Japan also includes voice calls.

Line uses a verification code to recognise your mobile number and cross-check it against your contacts. I didn't have any issue with it, arriving in a matter of seconds. For the time being, Line's user base is still minuscule in Europe so you'll be lucky to find more than a handful of your friends using it.

The others

If these four apps aren't enough, there are plenty of services offering free VoIP calls within its members. Apps like Tango, Rebtel, Foo, Truphone or Fring combine a paid model for regular destinations including some free offering for users of the same network. I cannot recommend anything in particular of this lot, as I rely on the four apps mentioned above. I'll keep an eye to see if any takes off, but for the time being I'm sticking with the popular ones where there's more change to find your contacts and avoid asking people to install an specific app.