Piton de la Fournaise Guide: Hiking into an Active Volcano

Piton de la Fournaise (2,632m) is one of the world’s most active volcanoes — erupting on average every 9 months, producing lava flows that have added measurably to Réunion’s surface area over historical time. Unlike most accessible volcanoes (which are dormant or fumarolic), La Fournaise erupts with regular frequency, producing genuine lava flows that visitors can legally approach to within a few hundred meters during the active phase.

Between eruptions — which is most of the time — the volcano is accessible via hiking trails that descend into the caldera (l’Enclos Fouqué) and climb to the active cone. The combination of lunar black lava, sulfurous steam vents, and the knowledge that this landscape was reshaped weeks or months ago produces an experience unlike any other European territory.

The Approach: Plaine des Sables

2 hours from Saint-Pierre by car | Road from Bourg-Murat

The standard approach to La Fournaise climbs from the town of Bourg-Murat (south-central Réunion) through the Plaine des Cafres agricultural plateau, then into the Plaine des Sables — a high-altitude red sand plain at 2,200m elevation that looks entirely unlike anything else on the island. The road across the Plaine des Sables (a dirt road that becomes impassable in heavy rain) crosses a landscape of iron-oxide red sand and eroded rock that has been compared to a Martian surface.

The road ends at the Pas de Bellecombe (2,311m) — the viewpoint and trail head on the caldera rim.

Road conditions: The Plaine des Sables road is regularly closed after heavy rain or during eruptions. Check the Préfecture de La Réunion website or OVPF (Observatoire Volcanologique du Piton de la Fournaise) for current access status before driving up.

The Pas de Bellecombe Viewpoint

From the parking area at Pas de Bellecombe, the view into l’Enclos Fouqué is immediate and dramatic — a volcanic caldera 8 km across, its floor entirely covered in black lava in various textures (the ropy pahoehoe and the jagged aa flows are both visible from the rim), with the active cone (Piton de la Fournaise itself) rising at the center.

On a clear day, the scale of the caldera is stunning — this is an active volcanic landscape at a scale that requires the elevated viewpoint to comprehend. The volcano observatory building is on the far eastern rim.

The Crater Hike

Distance: 11 km round trip (rim to summit and back)
Elevation gain: ~550m
Time: 4–5 hours
Difficulty: Moderate (difficult footing on rough lava)

The trail descends from Pas de Bellecombe into the caldera via a set of metal steps (installed to help with the steep lava rim), then crosses the caldera floor to the base of the active cone.

The caldera floor: Walking on the older lava fields — some from eruptions decades ago (overgrown with pioneer plants and mosses), some from recent eruptions (bare black rock, still sharp enough to damage footwear). The surface requires concentration — aa lava is extremely irregular and ankle-twisting.

The cone ascent: The active cone rises about 250m above the caldera floor on loose scoria (volcanic gravel). The ascent is steep and unstable; trekking poles help significantly. At the summit rim, the view into the active crater — including visible fumaroles, the smell of sulfur, and the cracked and deformed rim from recent activity — is the payoff.

When the summit is closed: La Fournaise erupts frequently, and when it does, the caldera trail is closed (legally — the Préfecture issues exclusion zones). Check access status at OVPF before hiking.

What to bring: Sturdy, ankle-supporting footwear is essential (sneakers will be destroyed by aa lava). Sun protection (no shade at altitude), minimum 2L water, warm layers (2,600m is significantly cooler than the coast even on warm days), and dust protection for the Plaine des Sables road.

During an Eruption

When La Fournaise erupts, the flow from the active cone descends through l’Enclos Fouqué and occasionally beyond the caldera walls toward the coast. Active eruptions on Réunion are rarely explosive — the basaltic lava is fluid and produces lava flows rather than ash clouds, making close approach relatively safe if managed correctly.

Helicopter viewing: The spectacular option — helicopter operators (Coralis, Helilagon, ICARE) fly over active flows during eruptions. 15–20 minute flights provide views of glowing lava, lava tubes, and new flow fronts. Cost: €70–150/person. This is genuinely extraordinary and not available at most volcanoes in the world.

Ground approach: When the Préfecture permits guided approach to active flows, specialized volcano guides offer walks to within viewing distance of active lava. This is situation-dependent and subject to rapid change; the OVPF website and local operators are the current information sources.

Access status: The exclusion zone system means even the Plaine des Sables road is closed during eruptions in the caldera. The trade-off is that, once an eruption ends, the fresh lava fields are accessible earlier than comparable sites in Hawaii or Iceland.

OVPF: The Volcano Observatory

The Observatoire Volcanologique du Piton de la Fournaise monitors the volcano’s activity continuously via seismometers, GPS deformation sensors, and thermal cameras. Their website (OVPF) provides:

Current activity level (from “pas d’activité notable” to “éruption en cours”)
Access status for the caldera and approach roads
Eruption reports with maps showing flow extents

Check this website the day before and morning of any planned volcano hike. Conditions change rapidly.

Combining with Cilaos and the Southern Cirque

La Fournaise sits in the southeastern quadrant of the island, accessible from Saint-Pierre (south coast) or via the island circuit from Saint-Denis. The Cilaos cirque is 2 hours west from Bourg-Murat — a logical multi-day combination covering Réunion’s two most distinctive geological features.

Three-day itinerary for the south:

Day 1: Drive to Bourg-Murat; afternoon hike or Plaine des Sables view
Day 2: Full crater hike (early start) or helicopter flight if erupting
Day 3: Drive to Cilaos (via Plaine des Cafres); explore the cirque village and hot springs