There are several places on St. John, especially on the north shore between Trunk and Cinnamon Bays, where your phone may pick up a signal from the British Virgin Islands that will result in exorbitant roaming charges. If you are in one of these locations, your phone will display “Lime” instead of AT&T, Sprint, Verizon etc. On my iPhone the name of the carrier and signal strength are displayed on the top left corner of the phone. Look out for “Lime” or Boat Phone,” they’re BVI-based and calls will be expensive. Ironically, when on Jost Van Dyke and parts of Tortola where the cell signal will be handled cheaply by US Virgin Islands carriers. Check your phone to make sure.
Besides calls, the other danger occurs when you’re using mobile data like Safari, Google, Facebook, email or any other internet based app and you inadvertently move to an area where you’re picking up a BVI signal, in which case your cost for the data will skyrocket.
The best way to prevent this is to simply turn of data roaming on your phone.
(Data roaming means using mobile data in another country where charges are considerably higher than in the US when using the Internet abroad.)
To turn off data roaming:
1- From the home screen tap Settings
2- Select General and then choose Mobile Data. On some iPhones, this might be called Cellular instead. On older versions of iOS, look for Network.
3- Choose Data Roaming and select Off
Go to Settings
Select Wireless & networks
Select Mobile networks
Make sure the Data roaming option is not checked