There are no rules against roaming charges, so it depends on the plan. I believe that most plans don't have roaming charges within the United States. Mine cert

There are no rules against roaming charges, so it depends on the plan. I believe that most plans don't have roaming charges within the United States. Mine certainly doesn't. It's hard to have a competitive plan that has roaming charges. Roaming charges outside the United States can be quite high. I have to watch carefully who I'm connected to when I'm near the Canadian border.