Aso-san Nakadake Crater is an active volcanic crater set inside one of the world's largest calderas, in the Aso region of Kumamoto, Japan. Its main draw is the emerald, strongly acidic crater lake — roughly 600m across and 130m deep — topped by white volcanic plumes and surrounded by a stark, Mars-like landscape. Because it is a living crater that constantly emits volcanic gas, viewing is frequently restricted, so checking whether it is open on the day of your visit is essential.
The emerald acidic crater lake and steaming white plume at the crater floor (color and water level shift with volcanic activity)
A barren, moon-like walking area around the rim and the volcanic-desert terrain of Sunasenrigahama
The rows of concrete emergency shelter bunkers along the rim — a signature sight of an active volcano
The nearby Kusasenri grassland, one of Japan's largest, with grazing cattle and horses and scenery that changes each season
Access via Kyusanko shuttle bus from JR Aso Station to Asosanjo; visibility is best on clear spring-to-autumn days
Good to know
SafetyThe crater emits toxic volcanic gases such as sulfur dioxide (SO2). Viewing is prohibited or discouraged for people with asthma, bronchitis or heart conditions, and for those who are pregnant or unwell.
RulesObey the traffic-light warning system at the rim (yellow = caution/restrictions for the respiratory-vulnerable; red = full closure) and never approach the rim on a red signal. Gas levels can force an afternoon closure even after a morning opening.
RulesDrone flights are banned within 1km of the crater, in the permanent no-entry zones, and across the whole of Sunasenrigahama.
Safety⚠️ On January 20, 2026, a sightseeing helicopter crashed into Nakadake's No. 1 crater, killing all three aboard (two Taiwanese tourists and the Japanese pilot). Since then, crater viewing and the Aso Volcano Park toll road have been closed, so confirm reopening on the official site before planning a visit.
RulesDue to emergency recovery work, Sunasenrigahama is scheduled to be closed to entry from June 15 to July 31, 2026 (tentative). Access rules change often, so always check the latest updates.
SeasonAt this high elevation temperatures are low and wind and fog can be strong. Expect road icing in winter and rapidly changing weather in summer; bring warm, wind-proof clothing.
Practical info
When open, the Aso Volcano Park toll road normally charges ¥1,000 for cars, ¥400 for motorcycles, free for bicycles, ¥2,800 for small buses and ¥3,300 for medium buses (disabled discount ¥500 for cars). Opening hours are seasonal (summer 8:30–18:00, autumn 8:30–17:30, winter 9:00–17:00, with gates closing a bit earlier). However, following the 2026 helicopter accident the toll road and crater viewing are currently closed; verify all fees, hours and restrictions in advance on the official 'Aso Volcano Crater Restriction Information' site (aso-volcano.jp).
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