Mount Aso

What to know

Mount Aso (阿蘇山, Asosan) is an active volcano in central Kyushu, with recent eruptions in 2021 and 2016. Its ancient caldera is among the world's largest, spanning up to 25 kilometers in diameter and over 100 kilometers in circumference. Inside the caldera rise several active volcanic peaks, including Mount Nakadake, whose dramatic crater is open to visitors.

However, the crater area is frequently partially or fully closed due to toxic volcanic gases, bad weather, or eruption risk. Always check the volcano's current status before heading out. Even when the summit area is open, gas levels can be high, and people with respiratory issues should avoid the crater.

Beyond the easily accessible crater viewpoint, a network of hiking trails leads to Mount Aso's various peaks. The most rewarding route starts from a parking lot near the crater and climbs to the Nakadake summit, about 350 meters above the crater, offering stunning views of the volcanic landscape.

The hike takes roughly 90 minutes and includes a very steep section. From Nakadake's peak, you can descend 20 minutes to a lower viewpoint near the crater or continue to Takadake, the highest peak of Mount Aso. Many trail sections are covered with loose volcanic stones, so proper preparation and sturdy footwear are essential. The trail may be partially or fully closed when the volcanic alert level is raised.

Near the Nakadake crater, Kusasenri (or Kusasenri-ga-hama) is a grassy plain with easy walking paths and a few horses. Horseback riding is available from early March to mid-December. Across the road, the Aso Volcano Museum provides exhibits about the volcano.

Komezuka is a small, beautifully shaped volcanic cone on Nakadake's northern slopes. Pleasant walking trails exist in the area (though not to the top), but public transportation access is limited.