I got an email from Xfinity today describing “Number Lock”.
I know you must have your phone with Xfinity Mobile, but it sounds like a good idea.
Here is how to enable it if you have Xfinity Mobile phones:
I wonder if something like this is available from Boost Mobile?
As far as I know, this isn’t a feature offered by any DISH/EchoStar brand.
Helium Mobile and, I think, US Mobile offer it. I’m sure there are some others but, for the most part, it’s still limited to those doing business with one of the big 3 directly.