Signed up for this mobile service and like it so far. fi.google.com $20 per month for unlimited calling and text within the US (and maybe other countries). No SIM card required. Works internationally. International call rates depend on where you are at but SMS to any number is unlimited and free in 135 countries. Data rates are a bit pricey at $10/GB but it is a nice feature as it automatically connects to the fastest available network in whatever country you are in. So far I know that it works in the US, Canada, Russia and China (got a message welcoming me to those countries as I flew over them). I suspect the only countries it doesn't work in are countries that most people have no interest in visiting. I think it only works on newer (expensive) phones. Not sure what will happen once I put in my Afghan SIM card when I get back to work but I'm hoping it acts like a dual SIM phone.
Google must be paying attention to what I'm typing as right after I posted this I got a notification saying "SIM not allowed"....even though I didn't insert a SIM card into my phone. I guess it is a good thing I didn't trade in my old Google Pixel phone. Will use that as my work phone. Maybe these screenshots will work. https://photos.app.goo.gl/tXhhIgnCsyg5hClT2 https://photos.app.goo.gl/fvSQT2jFKNLz3dy03 WiFi call rates: https://photos.app.goo.gl/pe56STgwV1DHxk5Z2