Using the internet on your phone while you are roaming carries a charge just as making a call and sending a text message does.
If you would like to avoid data charges, consider the following options:
1. Deactivate your data connexion.
2. Avoid unexpected data charges by switching off mobile data. If mobile data is switched on whilst you're connected to Wi-Fi, your phone could switch over to using the mobile data connection if the Wi-Fi signal is weak. When this happens, data charges as per roaming rates would apply.
Here's how you can turn off your mobile datas connection on your phone:
Step 1. Most phones feature the option to turn off your data in the top Notification bar. You can press this to turn mobile data off or on.
Step 2. You can also visit Data Usage in your phone settings.
Step 3. Alternately, you can visit Settings, More Networks, Mobile Networks and enable or disable data there.