Réunion is one of the few islands in the world you can cross on foot, ocean to ocean. Two long-distance trails make it happen: the GR R1, which loops around Piton des Neiges in six days, and the GR R2, the “grande traversée” — about 140 kilometres from Saint-Denis to Saint-Philippe through cirques, high plains and volcano country. Stages, huts, booking, season: here is the guide, figures checked in September 2026.
Two GR trails (plus a third) for one island
The heart of Réunion — its pitons, cirques and ramparts, a UNESCO World Heritage site since 2010 — is explored along paths carrying the classic white-and-red GR waymarks. Three routes share the work: the GR R1 circles Piton des Neiges (3,070 m, the roof of the Indian Ocean); the GR R2 crosses the island diagonally from north to south-east; and the shorter GR R3 loops around the Mafate cirque in two to three days.
None of them requires mountaineering gear: these are mountain footpaths — demanding but waymarked, and strung with gîtes where you eat and sleep. What makes them unique is the density: in one week of walking you go from a cirque’s dizzying ramparts to a cloud forest, then to a cinder desert that looks like Mars.
GR R1: around Piton des Neiges in 6 stages
The GR R1 is the ideal loop for a first big hike on Réunion: about sixty kilometres in six stages of 2 h to 6 h 30 of walking, starting and finishing in Hell-Bourg, in the Salazie cirque. The trail strings together the Bélouve cloud forest, the rim of the Trou de Fer, the heights of Cilaos, then Marla — Mafate’s highest hamlet — before climbing back towards Salazie via the Col des Bœufs and the Plaine des Tamarins.
The highlight plays out at the Caverne Dufour hut (2,478 m): sleep early, rise around 4 a.m., and climb the final rocky ramp by headtorch to the summit of Piton des Neiges for sunrise above the sea of clouds. The out-and-back from the hut is short but steep and stony, and it is cold up there before dawn — gloves and a down jacket are no luxury, even “in the tropics”.
GR R2: the great crossing, Saint-Denis to Saint-Philippe
The GR R2 is the masterpiece: the full crossing of the island, from the La Providence trailhead in Saint-Denis to Basse-Vallée, in Saint-Philippe on the south coast. Depending on the guidebook and the variants, count 135 to 143 kilometres — about 140 — and close to 9,100 metres of elevation gain, which most walkers spread over 10 to 12 days.
The menu is dizzying: the climb to Roche Écrite (2,276 m) with its plunging view over Mafate and Salazie, the crossing of Mafate hamlet by hamlet, the climb to Cilaos, the passage of Piton des Neiges via the same hut as the GR R1, then the high plains, the Plaine des Sables and the plateau of Piton de la Fournaise, before the long forest descent to the ocean. A whole island, summed up in one ridgeline.
The sections you never forget
Some passages justify the trip on their own. The Plaine des Tamarins, between the Col des Bœufs and La Nouvelle: a plateau of highland tamarind trees twisted by the wind, often in the mist, straight out of a fairy tale. Arriving in La Nouvelle, Mafate’s “capital”, where the morning helicopter delivers the bread. The Roche Écrite balcony at daybreak, when both cirques reveal themselves at once.
And on the volcano side, the Plaine des Sables: a dead-straight track through a desert of red and black cinders at 2,260 m, which the fog can swallow in ten minutes — the most “lunar” stretch of the whole crossing. If you are not walking the full GRs, each of these highlights works as a day hike: La Nouvelle is about 3 hours from the Col des Bœufs car park (11.4 km return, allow ~6 h in all).
Mountain gîtes: book early, sleep simple, eat well
The backbone of both GRs is the network of mountain gîtes: simple dorms, a generous Creole dinner (cari, rougail, rice — often the best meal of the day) and breakfast before dawn. In the online-bookable mountain huts, half board (dinner + breakfast) runs around €34 per adult, bed extra; at the Gîte du Volcan it rises to €40. In Mafate, expect €60 to €75 per person for the night with half board in a family-run gîte.
The golden rule: book well ahead, online or through the island’s booking platforms — weeks, even months for Caverne Dufour in the dry season. The balance is often paid in cash on site, especially in Mafate, where there are no ATMs and card terminals are unreliable. Bring water purification too: not every source is drinkable.
When to go, and the safety rules
The ideal window runs from May to November, the southern winter: drier trails, steadier skies, perfect walking temperatures — but cold nights at altitude, with frost possible above 2,000 m. The rainy and cyclone season (15 November – 30 April) soaks the paths and can close them for days; the east flank, which the GR R2 eventually reaches, receives 3,000 to 5,000 mm of rain a year while Saint-Gilles stays under 700 mm.
Three reflexes cover most of the safety. Start early: Réunion’s mountains are clear at dawn and cloud over by late morning. Check closures: after a rockfall or a cyclone, whole sections are closed by prefectoral order — check the trail status published by the ONF and the Département before each stage. And tell someone your route: there is no mobile signal in much of Mafate and along the ramparts.
Logistics — and a mad dream for the road
Both GRs work well with public transport: the Car Jaune buses (€2 to €6 per trip depending on the line, €15 for the pass) serve Saint-Denis, Cilaos, Hell-Bourg and Saint-Philippe, which spares you the puzzle of a car left at the trailhead. For a day trip into Mafate, the guarded car park at the Col des Bœufs costs €5 for the day, €14 overnight, cash only.
Finally, to measure what this island does to the strongest legs: every October, the Grand Raid sends its runners onto the “Diagonale des Fous”. The 2026 edition, from 15 to 18 October, stretches the race to 180 km and 10,200 m of elevation gain — the longest course in its history, skipping Cilaos this year. The best swallow in about thirty hours what the GR R2 will give you in ten days. Take the ten days: the Plaine des Tamarins deserves lingering.