We just left BVI yesterday by ferry to St Thomas. At this time, if you are taking the ferry back to St Thomas you need a covid test within 5 days. We did our self test during our "happy hour" at the bar at Anegada Reef Restaurant using their WiFi four days before our departure. You then need to feel out the USVI portal. All very easy. If you're flying out of the BVI, you have to test no more than one day out.