The Narusawa Ice Cave is a lava cave that was formed during the 9th century following an eruption of Mount Fuji. It was designated as a natural monument in 1929 by Ministry of Education, and is today a notable tourist attraction in the Fuji Five Lakes region.
The ice cave is 150-meters long and has an average temperature in the ice cave is 3°C. It is known for the icicles formed by the water that drips from the ceiling. Visitors are required to wear hard hats during their tour of the cave—a route that can be completed in under 10 minutes. This due to the low ceilings—as low as 1 meter in places—and slippery path. Caution is definitely advised as you move down towards the lower chamber. Please note that the Fugaku Wind Cave is also located a short walk away.