ST Call

ST Call lets SmarTone customers make and receive calls to Hong Kong over WiFi, saving roaming charges. You can use your own mobile number so the recipient sees your usual caller ID, and the other party does not need to install the ST Call app. It also works in Hong Kong where mobile signals can be weak, keeping you connected when networks are unreliable.

Key features include voicemail with alerts, call waiting while keeping your normal ringtone, and easy contact management by sharing your handset’s phone book. ST Call supports Dual SIM and eSIM, works in the background, and covers calling and receiving calls over WiFi. Availability is limited to SmarTone customers on designated service plans; note that third‑party WiFi charges and applicable IDD data for international calls may apply. The service is compatible with iOS 9.0+; data usage will be charged by SmarTone as per your plan.