On an island that doesn't have a single car rental agency, you get about by walking or riding a bike or motor scooter, which can be rented at hotels and in town near the pier.
There are also minibuses called taxis de l'Ile (eight in all), which take six to eight passengers. A taxi from the airport to the port at Bourg costs 12€.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.