Sierra Negra Volcano Hike, Galápagos: Trail Guide

If you do one hike in the Galápagos, make it Sierra Negra. One of the largest active calderas on Earth is on Isabela Island, and a trail leads to its rim and on to the steaming lava fields of Volcán Chico. It’s the best reason to see the islands on foot, land-based instead of only from a boat. Below is the trail brief, including the numbers other guides quote inconsistently.

Quick facts


Where	Isabela Island, Galápagos (highlands above Puerto Villamil)
Distance	~16 km round trip (rim + Volcán Chico)
Time	5–6 hours
Difficulty	Moderate: distance & heat, not the climb
Elevation	Max ~1,124 m · modest gain (not a high-altitude climb)
Caldera	~10 km across (~30 km around), one of Earth’s largest active
Guide	Required (national-park rule)
Best time	Year-round; drier underfoot Jun–Nov

What is Sierra Negra?

Sierra Negra is a massive shield volcano. It’s broad and gently sloping, built up over ~500,000 years from runny basaltic lava, and one of five shield volcanoes that form Isabela Island. From the rim you can’t take in the whole caldera. It’s a black sea of solidified lava running all the way to the far wall.

You’ll see its size quoted two ways, which confuses a lot of people. It’s roughly 10 km across (the diameter) and about 30 km around (the circumference). Both figures are right, and it’s one of the largest active calderas on the planet. It last erupted in 2018 (before that, 2005), so you’re walking on some of the youngest ground on Earth.

The hike, segment by segment

The trail changes as you go, and that’s part of why it’s so good.

Trailhead to the caldera rim. A steady walk on a dirt road, then trail, through humid highland scrub. After rain this first stretch gets muddy and slippery, and it’s the one awkward part. You climb gently to the rim, where the whole black basin opens up.
Along the rim. The trail follows the edge with the caldera dropping away beside you.
Rim to Volcán Chico. The trail crosses open, exposed lava out to the Volcán Chico vent area. There’s little shade and full sun.

Most people do the full route to Volcán Chico and back, about 16 km and 5–6 hours. Turning back at the rim makes it noticeably shorter, but you’d miss the best part.

Volcán Chico

Volcán Chico isn’t a separate volcano. It’s a parasitic vent on Sierra Negra’s flank, and it’s the highlight of the day. The lava here is young and brightly coloured: fields of red, ochre and yellow basalt in two textures geologists call pāhoehoe (smooth, ropey) and a’ā (sharp, broken). Fumaroles hiss sulphurous steam from cracks, and the views reach across Isabela to the sea. This is where every good Sierra Negra hike turns around.

How hard is it?

It’s moderate, but rarely for the reason people expect. There’s very little steep climbing and the elevation gain is gentle. What wears people out is the distance, the equatorial heat and the lava rock underfoot, plus the muddy start after rain. If you can comfortably walk 16 km on a hot day, you’ll be fine. It is not a high-altitude climb like Cotopaxi or Chimborazo on the mainland.

Do you need a guide?

Yes. Sierra Negra is inside Galápagos National Park, and a licensed naturalist guide is required for the trail. You can’t walk it independently. The guide reads the weather, knows the lava terrain and explains the geology and ecology of an active volcano as you walk. We arrange the guide, transport from Puerto Villamil and a boxed lunch as part of a land-based itinerary.

What to bring

Carry at least 2 litres of water, because there’s no shade and nowhere to refill. The lava radiates heat, so wear a hat and sunscreen. Pack a light rain layer for the showers that roll over the highlands.

Wear sturdy shoes with ankle support and grip, since the lava is sharp and the wet-season start is slippery. Long sleeves and snacks help. Your trip usually includes a boxed lunch.

Best time to hike Sierra Negra

It’s a year-round hike. The cooler, drier garúa season (roughly June–November) means firmer footing on the muddy first stretch. The warm season (December–May) is sunnier but wetter underfoot. In either season, start in the morning to avoid the worst of the heat on the open lava.

Sierra Negra is a geology hike, not a wildlife hike. You’ll see endemic plants and Galápagos hawks. If you’re after tortoises and boobies, pair it with the Wall of Tears trail lower down.

How it fits a multi-day Galápagos hike

Sierra Negra is the main event of a day on Isabela. It pairs well with the Wall of Tears and the island’s beaches and lagoons (see the full plan on our Isabela hiking page). It also fits into a multi-day, land-based Galápagos hiking itinerary that takes in Santa Cruz and San Cristóbal.

We plan our Galápagos hiking trips around walks like this one, so you spend the days on the trails and not on a boat deck.

Frequently asked questions

How long is the Sierra Negra volcano hike?

About 16 km round trip if you include the Volcán Chico extension, roughly 5–6 hours of walking with stops. The hike to the caldera rim and back is shorter (around 9–10 km), but almost everyone continues to the Volcán Chico lava fields, which are the best part.

How difficult is the Sierra Negra volcano hike?

Moderate, but not for the reason you'd think. There's very little climbing and the elevation gain is modest. What makes it tough is the distance, the heat and the lava rock underfoot, plus a muddy, slippery start in the wet season. Reasonably fit walkers handle it fine.

Can you hike Sierra Negra without a guide?

No. Sierra Negra is inside Galápagos National Park, and a licensed naturalist guide is required by law for the trail. The guide also handles the weather, the lava terrain and the geology. We arrange it as part of a land-based itinerary.

When did Sierra Negra last erupt? Is it still active?

Sierra Negra last erupted in 2018 (before that, 2005). It's still an active shield volcano, with steaming fumaroles at Volcán Chico, but it's safe to hike: eruptions are monitored and infrequent. You're walking on some of the youngest land on Earth.

What type of volcano is Sierra Negra?

It's a shield volcano, broad and gently sloping and built from runny basaltic lava. It has one of the largest active calderas in the world, roughly 10 km across, and is one of five shield volcanoes that make up Isabela Island.

What do you see on the Sierra Negra hike?

The black caldera from the rim, then the multicoloured lava fields and steaming fumaroles of Volcán Chico, with red, ochre and yellow rock in strange shapes. Endemic plants grow back over the lava, and Galápagos hawks often circle overhead. It's a geology hike first, wildlife second.

How do you get to the Sierra Negra trailhead?

The trailhead sits in the highlands above Puerto Villamil, about a 30–45 minute drive from town. A land-based trip includes the transport, the guide and usually a boxed lunch, so you just walk.

Is Sierra Negra worth it?

Yes. It's the best day hike in the Galápagos and the main reason to spend a day or two on Isabela on foot. If you like big landscapes and active geology, nothing else in the islands compares. It's light on big wildlife, so come for the volcano.