THE MOUNTAIN'S STORY
The 1968 Eruption and the Lava Fields You Can Walk
How a mountain thought to be a quiet hill blew apart one July morning — and the black ground you can still walk today.
See Arenal tours on GetYourGuide ↗The morning it woke
For more than four hundred years, Arenal was so quiet that locals thought it was an ordinary forested hill, not a volcano at all. Then, at half past seven on the morning of 29 July 1968, it blew apart. The eruption tore three new craters in the western flank, hurled multi-ton boulders more than a kilometre at around six hundred metres per second, and buried three villages — Tabacón, Pueblo Nuevo and San Luís — killing eighty-seven people. A mountain everyone had underestimated announced itself in a single, catastrophic morning.
Forty-two years of fire
What followed was almost as remarkable as the eruption itself: Arenal did not stop. For forty-two years, from 1968 until December 2010, it erupted near-continuously — one of the longest-running eruptions on Earth in the modern record. For four decades, watching glowing rock spill down the cone at night was the reason people came to La Fortuna. Then, in December 2010, the volcano fell quiet, and it has rested ever since.
Walking the 1968 ground
The eruption's most tangible legacy is the lava field itself, and you can walk across it. The Arenal 1968 Trail, on a private reserve beside the national park, crosses roughly 4.7 kilometres of the hardened lava the eruption laid down — black, twisted, otherworldly ground where pioneer plants are only now taking root, rainforest pressing in from the edges and the cone rising above when the cloud lifts. It's a moderate-to-difficult walk over rocky terrain, and it is the most direct, physical encounter with what the volcano did that you can have today.
Why it's worth doing
Standing on the 1968 field is a strange, quiet kind of awe. There is no drama in the moment — no glow, no rumble — just black rock underfoot and the knowledge that this was molten, that villages lie beneath ground like this, that the symmetrical green-flanked cone above you did all of it within living memory. In place of the fireworks the volcano no longer offers, it gives you something more sobering: the evidence, underfoot, of what a resting volcano is capable of. It's the heart of an Arenal visit.