Driving a car
If you can afford, a car rental is the best solution to get around on the island. A 4WD is not needed, not even for mountain excursions. However, be careful when driving in the mountains. Narrow roads, numerous bends (and landslides in some places), deep verges complicate the driving. Therefore drive carefully.
All the major rental companies are present at Roland-Garros airport in Saint-Denis. We strongly advise you to make a reservation in advance.
Many small local rental companies offer cars at much better prices, but their vehicles' condition can significantly vary.
There are frequent traffic jams on the coastal road between Saint-Denis and Le Port. With your rental car avoid entering cities, Saint-Denis, between 7 a.m. and 9 a.m. and leaving between 4.30 p.m. and 6 p.m. Massive traffic jams are expected on Sunday evenings between 5 p.m. and 8 p.m., on the coastal road linking Saint-Gilles-les-Bains to Saint-Denis and in the region of Saint-Pierre
Rent a motorbike
It is somewhat risky because the local driver doesn't respect the traffic rules, and motorbikers are more vulnerable.
A bigger problem: insurance doesn't cover motorcycle theft, and the rental companies mostly ask for by credit card a deposit of the larger motorcycle's market value. So, beware of theft, and try to assess the condition of the rented equipment.
Biking is not that easy given the relief of the island. The only roughly flat routes cover all of the coastal roads, but it's not easy due to the headwinds, the many false flats on the east coast, and fast-moving cars. In short, cycling on principal axes is mostly discouraged.
Nonetheless, in recent years, broad yellow bands have developed for cyclists along national roads, particularly between Saint-Paul and Étang-Salé-les-Bains or south of Saint-Pierre.
The island is very well served by public buses, especially to the west; less to the east, where you can't find much after 6 p.m. anyway).
There are two kinds of bus lines: roughly, those on the coast, the fastest and most important (this is Car Jaune), and those that serve the Hauts and the main towns' surroundings (by the way, very picturesque).