You can limit your data usage when abroad by deactivating data roaming. No connection to the Internet via the mobile network when abroad can then be established. You can still use WLAN even though data roaming is deactivated. Remember, you need to activate mobile data.
Activate or deactivate data roaming
Press "More" below "Wireless & networks".
Press Mobile network.
Press Data roaming to activate or deactivate the function.
If you activate data roaming:
Press OK to confirm.
Return to the Home screen
Press the home icon to end the session and return to the Home screen.