Apologies if there already exists a thread that addresses this. I will be on HAL ship for 14 days in Carribean in Jan '19. My mobile carrier AT&T offers $10/day international plan for phone/text including access to my plan's monthly data. Question: if I am in port and on the ship, how do I know if I'm using the AT&T plan through onshore cell towers or using the expensive Cellular at Sea connection? Also, what if the ship is not at dock/pier but instead is anchored offshore for tendering; would the possibility of accessing the onshore towers be unavailable? My intention is to only use $10/day plan for a few random days while in port, instead of paying for an entire HAL wi-fi plan or for the AT&T $100 cruise plan. I am unsure if I need to be physically off the ship and in town. I was also hoping to rent a car and be able to use my data onshore for google maps/navigating. Love love love you guys and CC. I've learned so much here. Thank you!