I am going on a cruise on Jan 21 and leaving Miami. We are purchasing the travel pass for my wife's phone for the week we are gone. We have the Unlimited plan which includes Mexico. We are traveling to Jamaica, and Grand Cayman as well. Every post I see on a cruise site, it says to turn off cellular or I would be charged by the cruise ship for using the ships service. How can she use her phone in these ports if the cellular is turned off? How could I use her phone without connecting to the ship? Do we turn off data roaming or does that need to be left on? I just don't want any surprises on my bill when we return? We have never been on a cruise or even left the country. Thanks for any replies.