Arenal: A Deep Dive into Costa Rica's Iconic Volcano
Arenal is the picture-book volcano of Costa Rica: a near-perfect conical peak rising above lush rainforest, hot springs, and a tranquil lake. Yet this serene postcard image hides a violent recent past. In 1968 Arenal awoke from centuries of slumber with a deadly eruption, and for the next four decades it was one of the most reliably active volcanoes in the world, drawing visitors to witness its nightly glow before it quieted in 2010.
A young and graceful cone
Arenal reaches about 1,670 metres and is one of the youngest stratovolcanoes in Costa Rica, its symmetrical conical form a textbook example of the volcano of the popular imagination. It rises within the Arenal Volcano National Park in the country's northern lowlands, surrounded by rainforest rich in wildlife and overlooking the large Lake Arenal, a reservoir that also supplies hydroelectric power.
The catastrophic 1968 eruption
For centuries before 1968, Arenal had appeared dormant, its slopes farmed and settled. Then, on 29 July 1968, it erupted violently and without warning, blasting open new craters on its western flank and sending pyroclastic flows and ejected rock across the surrounding area. The eruption destroyed villages and killed scores of people, an abrupt and tragic reawakening that announced the volcano's return to life.
Decades of near-constant activity
After 1968, Arenal settled into a long phase of near-continuous activity that lasted until 2010. It regularly produced lava flows, Strombolian explosions, and glowing rockfalls, especially visible at night. This reliable activity made Arenal internationally famous and turned the nearby town of La Fortuna into a major tourism hub, as visitors gathered to watch incandescent rocks tumble down the cone after dark.
The town of La Fortuna
The growth of La Fortuna is inseparable from Arenal's activity. The town transformed from a quiet agricultural settlement into one of Costa Rica's premier tourist destinations, built around the volcano, its hot springs, and the surrounding rainforest. Even after the volcano's eruptions paused, the region remained a cornerstone of Costa Rican ecotourism, drawing travellers to its adventure activities and natural hot springs.
The 2010 pause
In 2010, Arenal's decades-long eruption came to an end, and the volcano entered a phase of relative quiet. While this disappointed visitors hoping to see glowing lava, it is a normal part of a volcano's behaviour. Arenal is not considered extinct; it is simply resting, and scientists continue to monitor it for any signs of renewed activity.
Hot springs and geothermal heat
The same volcanic heat that drives Arenal's eruptions also feeds the region's famous hot springs, where mineral-rich water warmed deep underground rises to the surface. These springs have become a major attraction in their own right, allowing visitors to soak in naturally heated pools in the rainforest, a soothing counterpoint to the volcano's more dramatic moods.
Monitoring and the future
Costa Rica's volcanological and seismological institutes monitor Arenal alongside the country's other active volcanoes, watching for the seismic and deformation signals that would herald renewed activity. Costa Rica, sitting on the volcanic arc of Central America, takes volcanic monitoring seriously, and Arenal remains an important part of that watchful network.
Explore on the map
Arenal stands among Costa Rica's chain of volcanoes, alongside Poas, Irazu, and Turrialba. Explore it on the interactive map — filter by country to see Arenal among Costa Rica's volcanoes and to place this iconic cone within the volcanic arc of Central America.