It's nearly impossible to see either island without renting a car. Note that you cannot rent a car on mainland Puerto Rico and bring it across on the ferry; you'll need to rent from a local agency, all of which specialize in SUVs. Most agencies also rent golf carts, though these aren't an ideal way of getting around if you want to explore the beaches. Road conditions and local driving habits are spotty. Rates are between $50 and $95 a day. It's often cheaper to book a hotel-rental car package. Be sure to read Culebra and Vieques rental car companies' rules, as off-pavement driving has recently been prohibited by many companies, and violations will result in a fine. Both islands' rental car companies also impose fees for excessive sand and/or water inside the vehicle.