Best answer by Dinh
That is the case in an ideal world. Easyroam will charge when you use data/send text/make or receive calls https://www.koodomobile.com/easyroam
However, there could be many issues with accidental usages that you need to take care of if you choose to use easyroam intermittently:
- Some phone could send text to server for extra services (iphone and some android phones), that would trigger easyroam even if you don't send text yourself.
- Some phone could use tiny amount of data when you turn on/off or switching between towers. It could trigger easyroam for that day also.