The British Virgin Islands maintain a separate border control with United Kingdom. Nationals of Canada, EU, New Zealand, Singapore, Japan, South Korea, Switzerland, United States of America etc. do not require a visa to enter and visit the British Virgin Islands. Other nationals require a visa. For more detailed information, refer to the following website for more details (http://www.dgo.gov.vg/ind...).
Passport and visa regulations are enforced at harbors, especially for boats moving back and forth between the US and British territories. US customs may tell you a certified birth certificate is acceptable, but as of June 2009, ferry operators can only take passport carrying US citizens or face a CBP.GOV $3,000 fine. (http://www.robertwray.com...) US CBP.GOV offices in St. Thomas. (http://www.cbp.gov/xp/cgo...)
Boats move freely between the BVI and the U.S. Virgin Islands. A few cruise ships visit the major ports, but small vessels are more common.
Ferries move between Tortola and St. Thomas. There are several different ferry companies that provide service between the two islands. These ferries are what connects the people of the British Virgin Islands with the people of the U.S. Virgin Islands. The ferries link the city of Charlotte Amalie, St. Thomas with either Road Town or the West End of Tortola.
The ferry is one of the more popular ways to reach Tortola from the U.S. This is due to the fact that Americans can reach Tortola via only one direct flight and then a short ferry ride. This will no doubt save the traveler several hundred dollars, since a second flight would not be necessary.
You can catch one of the ferries, almost any time of day. After 5PM most of the services are shut down for the evening. The ride lasts about 50 minutes depending on the weather. The scenery is well worth the price of the ride.
One-way ranges from $25-$30 for adults, $19-$25 for children
Round-trip ranges from $45-$52 for adults, $30-$42 for children
Vary greatly between companies. Some of the companies even alternate their schedules between themselves and another company. For a current list take a look at this page's ferry schedule (http://www.vacationtortol...).
Many travelers find it easier to just buy two one-way tickets from different companies instead of one round-trip ticket with the same company. Since ferries from different companies are coming and going constantly, you should be able to catch a ferry at any time during the day. Often times one company will be convenient upon arrival, but not upon departure. Just check the schedule to find out if this will be the case for you, if not then by all means, buy the round-trip ticket and save a few bucks.