Does the Apple Watch need a separate telephone number than your iPhone Number?

Hi

No, it does not. It uses the same phone number as your paired iPhone.

Even when using a different Apple Watch model that has a built-in cellular feature, it still uses the same phone number.

More information is provided below.

Intro

There are two different versions of Apple Watch Series 3:

• Apple Watch - Compare - Apple
• Apple Watch Series 3 - Apple

All models of Apple Watch can be used to make and receive calls when your iPhone is nearby and, potentially, other certain other circumstances (see below):

• Answer phone calls
• Make phone calls

Apple Watch Series 3 (GPS) - which you asked about

Apple Watch Series 3 (GPS) models do not have a built-in cellular capability.

Any calls or data-related services are routed either via the paired iPhone or via a direct connection between the watch and a compatible Wi-Fi network (when the watch cannot connect to the paired iPhone via Bluetooth).

Specific support for the Apple Watch is not required on the iPhone's cellular plan.

An iPhone 5s or newer model of iPhone is required, running the latest version of iOS.

Apple Watch Series 3 (GPS + Cellular)

Apple Watch Series 3 (GPS + Cellular) also always first tries to use the Bluetooth connection to your iPhone (which does not require a separate plan for the watch) or, in the absence of that, any available connection to a compatible Wi-Fi network.

If neither of those is available, then Apple Watch Series 3 (GPS + Cellular) has a built-in cellular capability that, under certain circumstances, can enable calls and certain other features, which are not available on GPS-only models, to remain available when the watch is used without the iPhone nearby.

In order to be able to use the built-in cellular feature, you would require a carrier service plan for your iPhone that specifically includes support for the Apple Watch, including the carrier first activating the device on the plan:

• Set up and use cellular on Apple Watch Series 3 (GPS + Cellular) - Apple Support
• Use Apple Watch with a cellular network—Apple Watch Series 3 (GPS + Cellular) only

The same phone number is still used for the Apple Watch.

Apple's list of supported carriers is here:

Apple Watch - Carriers - Apple

Apple Watch Series 3 (GPS + Cellular) can also be used without enabling the built-in cellular feature, in which case it functions like a GPS-only model and can be used in conjunction with a service plan for iPhone 6 or newer model of iPhone, running the latest version of iOS, from any carrier, with no need to activate the watch on the plan.

Both model types

The functions that are available on your Apple Watch when it is away from your iPhone depend on various factors including:

• Your Apple Watch model:

  Apple Watch - Compare - Apple

• The features of your carrier service plan:
  • Apple Watch - Carriers - Apple
  • Make a call with Wi-Fi Calling - Apple Support
• The type of connectivity that is available to your Apple Watch at the time:

  About Bluetooth, Wi-Fi, and cellular on your Apple Watch - Apple Support

Features and requirements that apply under various circumstances are detailed here, including within the footnotes:

How to use your Apple Watch without your iPhone nearby - Apple Support

Yes, it is a separate phone number, but it is then synched with NumberSync if it is an AT&T phone. Works very well, I believe it is an additional $10.00 a month.

This link may be helpful

Use NumberSync to Sync Apple Watch Series 3 to a ... - ATT.com