Question AT&T Cell Service Abroad for Google Maps?

I'm planning a two-month trip to France and Italy and really need reliable cell service to use Google Maps for navigating the cities. I'm currently with AT&T and wondering if anyone has experience using their service abroad, especially for data-heavy apps like Google Maps. How was the coverage and speed? Did you find it sufficient for navigation, or did you have to look for alternatives? Any tips or advice would be super helpful!