Originally Posted by
freecia
For those thinking about picking up an Apple Watch Series 3 to pair with an older iPhone- the LTE model only has LTE in the country of purchase. You'd probably want to avoid purchasing a Japan iWatch Series 3 LTE if using it mostly outside Japan (also, I'm guessing you'd probably need a Japan residence card for a device cellular contract)
https://www.macrumors.com/2017/09/15...e-limitations/
OK interesting data point. Reading the thread it appears to be because Apple is using a Voice over LTE standard which is not yet internationally standardized hence the roaming issues.
And yes absolutely no chance of getting a cellular contract in Japan unless you've got a visa / residence card and a fixed address in Japan.
Docomo for example is doing 6 months free then charging 500 yen to add it to your existing iPhone contract from next year.