Activating your Xfinity modem is a straightforward process that can be completed using the Xfinity app or through a web browser. Open a web browser and go to https://register.xfinity.com/activate
Here’s a step-by-step guide to help you get online quickly:
📱 Activate Using the Xfinity App
Download the App: Install the Xfinity app from the Apple App Store or Google Play Store.
Sign In: Open the app and log in with your Xfinity ID and password.
Start Activation:
Tap on the Account icon in the bottom-right corner.
Select Activate xFi Gateway or Modem under the Devices section.
Follow Prompts: The app will guide you through the setup process, including scanning the QR code on your modem or entering the 12-digit CM MAC address.
Set Up WiFi: Once activated, you’ll be prompted to create a WiFi network name (SSID) and password.
Complete Setup: Wait a few minutes for the modem to finish the activation process. Once the top three lights on your gateway are solid, your device is ready to use.

Also Read : starz.com/settings/manage devices
💻 Activate via Web Browser
If you prefer not to use the app, you can activate your modem through a web browser:
Connect to the Modem:
Use a computer or mobile device to connect to the modem’s default WiFi network.
The default network name (SSID) and password are usually printed on the modem’s label.
Access Activation Page:
Open a web browser and go to https://register.xfinity.com/activate.
Enter CM MAC Address:
When prompted, enter the 12-digit CM MAC address found on the modem’s label.
Follow On-Screen Instructions: Complete the setup by following the instructions provided on the activation page.
📞 Activate via Phone Support
If you encounter any issues or prefer assistance:
Call Xfinity Support: Dial 1-800-XFINITY (1-800-934-6489).
Provide Information: Be ready to provide your account details and the modem’s CM MAC address.
Follow Agent Instructions: The support agent will guide you through the activation process.
🛠️ Troubleshooting Tips
Check Connections: Ensure the coaxial cable is securely connected to both the wall outlet and the modem.
Power Cycle: Unplug the modem, wait 30 seconds, and plug it back in to reset the device.
Verify Activation: If the modem’s lights are blinking orange or red, it may not be activated. In this case, contact Xfinity support for assistance.