Drive on the left. This catches many visitors off guard — the USVI is a US territory but inherited the left-hand traffic rule from the Danish period. Rental cars have the steering wheel on the left (American style), so you'll be driving on the left from the left seat. Take it slowly until you're comfortable.
Between islands by ferry. Frequent ferries connect St. Thomas and St. John; the crossing from Red Hook (eastern St. Thomas) to Cruz Bay (St. John) takes about 20 minutes and runs roughly every hour from early morning to around 11pm. Ferries also run from Charlotte Amalie (downtown St. Thomas) to Cruz Bay, taking about 45 minutes. The St. Thomas–St. Croix route is longer; ferries and the VI Seaplane Shuttle both make the run. Ferries to the British Virgin Islands (Tortola, Virgin Gorda, Jost Van Dyke) depart from Charlotte Amalie and Road Town.
Rental cars. The best way to explore any individual island. Available at both airports and in the main towns. You need to be 25 or older and hold a valid driver's license. Roads on St. John are steep and unpaved in places — a 4WD or high-clearance vehicle is useful. Finding a parking space in Charlotte Amalie during the day can be frustrating.
Taxis. Abundant on all three islands. Taxis charge fixed rates based on destination and number of passengers — agree on the fare before you get in. On St. Thomas, open-air safari taxis (flatbed trucks with bench seating) are a common and cheap way to get between major spots.
Buses. VITRAN buses serve St. Thomas and St. Croix with roughly hourly service on main routes from early morning to evening. On St. John, a limited service connects Cruz Bay with Coral Bay and Salt Pond Bay. Buses are cheap but slow, and schedules can be unreliable.
Seaplane. The VI Seaplane Shuttle offers a scenic and quick connection between Charlotte Amalie harbor and Christiansted harbor on St. Croix — far faster and more enjoyable than the ferry for that route.