Hiking
Reunion Island has almost one thousand kilometers of hiking trails, with an astonishing variety of landscapes for an island. The cirques, plains and volcano have been classified as a french national natural park. The best hikes are probably in the Mafate cirque and on the volcano see Piton de la Fournaise. The exceptionnal Mafate circus has no roads, and about 800 inhabitants.
You can find hostings on main hiking places.
Aircraft
Some helicopter and airplane companies do touristic flights. These depart very early in the morning in order to avoid clouds and fog at altitude.There are also some helicopter trips, e.g. to La Nouvelle in Mafate.
By bus
Intercity bus travel around the island is served by Car Jaune "Yellow Bus", buses are easily recognizable by their yellow color. There are 13 lines. Apart from these buses there are also local buses. Most of lines operate between 6AM and 6PM. You can get schedules and details on their official website (http://www.cg974.fr/defau...). Click on "Plans et tarifs" for a map of the network.
Car Jaune, Ligne B, from Saint-Denis to Saint-Pierre and back, Par les Bas via the coast. Operates approximately every one and a half hours.
By car
There is one main road around the island 74km of it is four-lane and another road from Saint-Pierre to Saint-Benoit route des plaines through the interior of the island.
Due to the high number of cars, traffic jams often occur so you should avoid travelling during peak times.
Because of the volcano, the road is sometimes closed along the east side of the island.
The four-lane highway between La Possession and Saint-Denis, known as the route du littoral, runs between an unstable cliff and the sea. Because of the rain mostly between December and March, this highway may be "basculée", that is switched to a two-lane road. Expect traffic jams in such circumstances.
Do not underestimate driving times, even if the island seems small. The main roads, especially on the west coast, tend to jam; so do the streets of Saint Denis. The roads in the interior are mountain roads, some with many turns and steep slopes.
Car hire is available.