OnStar is a provider of in-vehicle security protection, vehicle navigational systems and hands-free calling. OnStar services are in the United States, Canada and the People's Republic of China. OnStar's Hands-Free Calling is built-in voice-activated call-system vehicle hardware. Hands-Free Calling allows you to send and receive "hands-free" phone calls from your vehicle. You can find your OnStar phone number by using the vehicle hardware.
Get in your vehicle.
Press the "Phone" button, or white dot, on your OnStar system.
Say "My Number" when the OnStar system says "OnStar Ready." The OnStar system repeats your phone number back to you.