Datos internacionales

Currently travelling in Italy and upon arrival I received the standard welcome message “Your plan includes coverage that gives you unlimited data On Us now at faster speeds up to 256Kbps, plus unlimited texts at no extra cost!”  

Just want to make sure that I am reading this correctly, I have free text and data while here? What if I make a call through whatsapp or FB?

As long as I don’t make a call through the local carrier then I should not have any additional charges, correct?