How to find out iPhone watch number

deggie wrote:

But if you don't want to go through all the looking up just get the 3 numbers from your bill and call each one.

Many networks lock the direct number for the watch so it can only receive calls shared with the iPhone using the iPhone number. If that is the case, the solution might be to contact the network ands trace them using the IMEI (Settings, General, About).

An easier clue if the watches are working and paired to the correct iPhones would be to look for the IMEI in the watch (Settings/General/About) and also in the iPhone’s Watch App (My Watch/General/About). This should take about 3 minutes for each device and avoids having to explain to network call centers who may have trouble understanding what is needed.

That is not correct there is a phone number assigned to your Apple Watch GPS+Cellular and is should be listed on your bill and tied to the device. But if you don't want to go through all the looking up just get the 3 numbers from your bill and call each one.

There are no separate phone numbers for the watch. Whatever the phone number is for your iPhone is what is used for billing purposes.

I unfortunately made the assumption that the OP was in the US. AT&T has even removed this restriction recently.