Mobile number porting allows you to retain their mobile number even if they switch from telco A to telco B. It saves you the hassle to update your contacts if you switch service provider.
Typically, it will take around 1 – 2 working days for the number to port from telco A to telco B upon successful delivery of your sim card (excluding weekends & public holidays) and subject to approval by the original telco.
All customers are able to enjoy this service as long as their service is still active (not suspended or terminated) with the original telco. However, there may be some service disruption when your number is being ported to the new telco.