Using Viber and WhatsApp abroad to talk for free… or not?

What are the data roaming charges using Viber and Whatsapp? In previous posts I have covered the multi-platform apps that allow you to communicate with others without using your carrier's precious minutes and SMS plans. The magic behind it lies on placing your calls over the internet using your data plan, making reaching certain destinations significantly cheaper. The same people who pay $300 for a smartphone with a monthly contract also like free stuff, right?

The popularity of these two apps is unparalleled: Viber has consistently been one of the most downloaded Social Networking apps in virtually every App Store around the world while the WhatsApp Messenger has a love affair with the #1 spot in the charts, challenging the almighty Angry Birds. 

Both Viber and Whatsapp have become some of the most used apps in my iPhone since they offer the convenience of being in my pocket and a pricing strategy my carrier won't match. Having friends and family abroad also means that I can stay in touch at a much lower rate without having to schedule Skype calls or worry about compatibility issues texting to other devices.

Bandwidth usage

And since this "international factor" represents the biggest savings for many, I want to use the post as a reminder about how VOIP – the technology powering Viber – really works and some confusions about using it abroad. Since every call is routed using your current internet connection, you can take advantage of the included data plan in your contract and its low bandwidth usage. According to Viber's knowledge base articles, the app uses approximately 240 KB per minute, something like 14 MB per hour. 

I couldn't find any official statement about texting, so I have ran my own simple test to monitor cellular network data usage with both Viber and Whatsapp. It seems that texts have a low data consumption, ranging from 1.0 KB to 3.0 KB for both apps. I suspect Whatsapp uses more data since it runs in the background to verify who's online and update the latest messages – for me that was 13 KB in one launch. 

In my case, using my iPhone with O2 in the UK, my contract has a 500 MB cap per month, although you can also get one gigabyte with top tier contracts. The original iPhone, 3G and 3GS came with unlimited data plans, but obviously these apps weren't around yet. This means that every month I have 35 hours of international calls included with my contract, assuming I use it on the road connected to O2's 3G network. Obviously using Wi-Fi at home wouldn't count towards that.

Roaming charges apply

The main problem and very common misunderstanding comes now in the summer when many people go abroad on holiday. Since I can calls my friends abroad for free, I must be able to call home for free, right? Not so fast. Once you leave your country and connect to a different network, everything is subject to higher rates. Roaming charges apply when you are away from your home location and your carrier has to "borrow" the infrastructure from another operator.

If you have ever faced the situation, you know that roaming isn't going to be cheap. Starting with higher tariffs outgoing and even incoming calls, the network data usage is also affected. In my case, traveling to Spain or France, I'll pay £3.06 per MB and £6 per MB for countries outside Europe. A quick calculation shows that using Viber while roaming in Europe will cost me £0.75 per minute. Yes, and that's both to call and receive. 

Turning data roaming off

Don't think that O2 and other operators are so evil that they won't tell you about it. Every time I get to my destination, I get an SMS reminder to turn this feature off and avoid the ridiculous fees. This is as simple as going into the Settings menu, tap on General, select Network and slide that switch that says Data Roaming. 

This is such a serious issue for the end user that even Apple has acknowledged the situation, including a short description saying "Turn data roaming off when abroad to avoid substantial roaming charges when using email, web browsing, and other data services".

The lesson learned todays is that we can continue to use Viber and Whatsapp abroad for free, but not when we're out and about. Don't forget to turn off the data roaming to get nasty surprises when you return from your holiday, and take some time to explore places with a free public WiFi available to connect to the internet. Airports, hotels and even the odd Starbucks are always good spots for free internet access, keep data roaming turned off, as you can connect to a WiFi network without enabling that feature.