IDD
Any International Calls, SMS & MMS made and received while in Singapore.
Global Fees
For iPhone users, to activate iMessage for a phone number, the device sends a silent SMS with a verification code.
When the pop-up below is shown, it uses an SMS to activate iMessage with your phone number and once activated you can be contacted via iMessage/FaceTime using your phone number.
To avoid global fees, you can choose to opt-out from using iMessage by clicking "Cancel" when the above pop-up is shown on the phone.