As long as your phone’s data is turned off, then you cannot be charged for any data roaming charges, even with Wi-Fi enabled. You may still be able to send and receive phone calls and text messages. This means depending on your cell phone plan, you might still get charged. To be completely sure you won’t be charged, you should enable Airplane Mode. In other words, the safest way to use your phone abroad is while you are in Airplane Mode. No carrier fees will apply, and you still can enable Wi-Fi.