Does Changi Mobile support IDD? Yes, you can find our IDD rates on the Changi Go mobile app (Home > Mobile > IDD). What are the IDD destinations covered by Changi Mobile? What are the rates? You can find our IDD rates here. Alternatively, you can view the list under "IDD" in the Changi Go mobile app. The credit amount in your IDD Credit Pack will be deducted based on your call duration and the call rate displayed, by destination. Can I buy an IDD Credit Pack without a Changi Mobile’s mobile plan? You will need to sign up for a Changi Go Mobile Plan before purchasing any IDD Credit Pack. How do I make payment for an IDD Credit Pack? You have to purchase an IDD Credit Pack in the Changi Go mobile app. Payment has to be successful before you can use the IDD Credit Pack. We will deduct payment from the payment card stored in the app under your account. When is my IDD Credit Pack activated? Your IDD Credit Pack is activated instantly upon successful purchase, ready for your immediate use! What is the validity of my IDD Credit Pack? Your IDD Credit Pack is valid for 30 days, including day of purchase. How do I make IDD calls after purchasing IDD Credit Pack? To make IDD calls, simply dial + < country code > < number >.