Though technically on Beef Island [1], Long Bay is easily accessible from Tortola [2] and is one of the most popular beaches among visitors and residents. The fine white-sand bay forms a perfect half moon, providing plenty of elbow room even on the busiest days of the year. The water is almost always calm, but the sea bottom slopes steeply, making it important to keep a close eye on children and inexperienced swimmers.
Long Bay is ideal for long walks, and there can be rewarding beachcombing at the far eastern end. Coconut and sea grape trees provide plenty of shade, but there are no permanent restaurants or bathroom facilities. Its location next door to the airport means that you can hear the sounds of departing and arriving aircraft, and sometimes see them too. In 2005, the government bought nearly 100 acres of land around the beach to protect it from development.
Links:
[1] http://www.moon.com/destinations/virgin-islands/tortola/sights/beef-island
[2] http://www.moon.com/destinations/virgin-islands/tortola