There are no rental cars available on the island.  Rather, golf carts are the main mode of land transportation.  Golf Carts can be rented at various independent agencies in San Pedro, at hourly or daily rates.  Expect to spend about $80 USD to have a Golf cart for a full day.  Many resorts outside of town also offer cart rentals to guests.  Be sure to get a gas powered cart rather than an electric one if you plan on driving long distances along the island.

Taxis do circulate around the airport, town centre and to the south end of the island - they cannot cross the bridge to the north end.  They are all minivans, marked with an official seal, and have a green licence plate.  Water taxis and a regular ferry service the resorts to the north of the island.

Almost everything in town is within walking distance, but there are a growing number of good restaurants outside of the town centre which will require a taxi, water taxi or golf cart depending on where you stay. Most taxi fares are $5-10

Most resorts will arrange for your transfer from the airport, so you shouldn't have to worry about finding or paying for a taxi yourself on arrival.