Is important that your iPhone is unlocked, otherwise you cannot use it with another cellular service other than for original service that you bought it with. You can get a local Jamaican cellular service (with a Jamaican phone number) at very reasonable price to call locally and to call home. Way they connect Jamaican cellular service to your cellphone is replace something called a "SIM" card which they sell and install for you. I recommend either going to a "Digicell" or "Lime" store to get their cellular services in Jamaica. I don't remember exact cost but I think $30 will get you more minutes than you can use. Hope you have a great vacation.