I travel for China now and don't have any local SIM. I have my Japanese carrier's SIM put in my iPhone but set data roaming off. I use Wi-Fi in hotel.
However, I can use GPS while traveling around in my iPhone. In this case, can I play Pokemon Go while traveling? Or is mobile data required to play the game?
While I travel for China right now, I want to make the post more general. So please consider another country such as Australia, if China doesn't fit the question.