Using 'whats App' instead of international text/call plan?

If WhatsApp has the same capabilities as Skype, meaning if you are connected to the Internet you can call anyone, then sure. With Skype, calls to another person connected via Skype are free. If the receiving party is not connected via Skype(e.g. landlines and cell phones) there is a charge. See the rate sheet. I use WhatsApp for messaging and sending photos and don't know about phoning. Other posters?

You can make calls, video or voice with whatsapp just like skype.

Yes, WhatsApp is great for communicating that way (make sure your friends/family have WhatsApp themselves!).

Elizabeth, I traveled for five weeks in Europe only using wifi instead of an international plan through Verizon. As long as you have wifi you are good to use whats'app. For some reason I had a problem with people showing up on my list of friends once we both had downloaded the app. They could see me but I couldn't see them. They ended up having to send me a message first to make a connection. I got that all squared away before traveling.
I also used facebook messenger on wifi to both message and make video calls with friends on facebook. Both apps worked like a charm.

WhatsApp is easy to use - but it only works if the people you're calling have it too

What's App works fine -- as others have said, you need your recipients to have it as well. As long as you have wifi you can use that, Facebook Messenger, etc. Just be sure to disable your cellular connection so you don't get charged for international data use. Your carrier can talk you through the process; I used to physically remove my sim card when I traveled to avoid any mistakes. (Now I use Project Fi, a carrier that lets me use my phone internationally for the same price as in the U.S.)

Great! Thank you!😊

It's not clear to me that WhatsApp calls are currently possible to those not connected via WhatsApp such as landlines and mobile phones. I make those type calls using Skype after forwarding a small credit ($10) to cover the very modest charges of those calls. I use it often to call about the world. Works very well. Technology at it's best.

Google hangouts for texting and Google voice for calls works the same way. Video calling also available. We have used on our last 3 trips.

Whatsapp use requires that contacts are set up and ready to recieve/send your messages and calls. We used this solely while travelling in Europe for 17 days without cost. At times Wi-Fi was weak therefore WhatsApp was slow. For us this was the best option especially keeping cost down.

I found that I couldn't complete WhatsApp calls (either receiving or sending) when my phone was connected to a blue tooth device. When I was calling from USA to Italy, the person answered but couldn't hear me. Receiving calls, my phone WhatsApp would ring, but then disconnect. I closed the blue tooth connection and then was able to call. I figured this out after the friend had returned from Italy, Since then I have done calls to/from Canada completing only after shutting off Bluetooth. (Usually I have my cell phone Bluetooth connected to my land line so that the land line rings and I hear it even when the cell phone is not near me.)

Texting still works so someone could text the receiver to disconnect Bluetooth and expect a call, or to call back.

This may be a Skype specific issue but I've found that call quality degrades to unusable when the internet connect is overloaded or there's insufficient bandwidth. I find that about 15% of the time hotel wifi is unusable. So if calling home is important then you should consider having a backup plan. I usually get a local SIM card as a backup to wifi and to use when I'm out and about.

Elizabeth,

Using any Wi-Fi application may not be entirely reliable in all locations. I've found that the quality of the Wi-Fi varies between locations, and if you get a slow connection or there are a lot of users trying to access it at the same time, the service may be "less-than-desirable".

Given the fact that call recipients will also need to have What's App, an international call/text plan will be the easiest and most reliable option. If you also want data, the cost will probably be higher.