Some Verizon phones (mainly older or less expensive ones) will be CDMA2000 only, no GSM or LTE service
. Others will require an optional SIM card to use those services. It might pay to contact BTC at BTC Bahamas
and enquire what they support, after checking with Verizon for what your phone supports. And if roaming is still $2.99 a minute, it may pay to buy a cheap
GSM phone and a native SIM card anyway, fwiw. Different phones also may require manually selecting a network, i.e. going into a setup menu on the phone and switching from 'Verizon" to "BTC" once you are there. And entering technical information with that. As mentioned, something a BTC office could do for you. Or could give you instructions to do. Even here in the States, just replacing an AT&T SIM with one from T-Mob is often NOT good enough to make the phone work on the other carrier, without manual intervention.