The watch phone number is shown on the screen when the watch is not yet registered and activated. If the watch phone number is not shown on the screen, you will see a SIM ID number. With this SIM ID number, you can also complete the registration of the watch. 

Once the watch is activated, you can always find the watch phone number in the user portal (, where it is shown beside the Smartwatcher logo, after the name of the watch wearer, or under "Account details".