Many crewed yachts have cell phones on board and their usage policies range from limited to unlimited. It’s best to ask beforehand if you foresee lengthy stateside chats.
Depending on the anchorage and line of sight propagation, your stateside cell phone may work without roaming charges or by converting to BVI’s CCT Boat Phone. Due to the mountainous terrain, there may be black holes with no reception. The stateside cellular companies doing business in the USVI are Sprint and AT&T. You should check with your own provider for information on international roaming and roaming charges while in the BVI.