Are there actually bats in the cave?

Bat populations have significantly declined due to tourism. Sightings are now rare. The name reflects the cave's historical bat colonies rather than current wildlife presence.

How difficult is it to walk through the cave?

The self-guided route takes 15 to 20 minutes. The cave has low ceilings requiring stooping and an uneven floor. Hard hats are provided and required. Not suitable for those with severe mobility limitations.

What should I bring when visiting the cave?

Bring a flashlight for better visibility, sturdy closed-toe shoes with good grip, and warm clothing as the cave stays around 3 degrees Celsius year-round. Hard hats are provided at the entrance.

Is the cave wheelchair or stroller accessible?

No. The natural terrain includes uneven rock surfaces, narrow passages, and low ceiling sections that require bending. The cave is not equipped with ramps or smooth pathways, making it inaccessible for wheelchairs and strollers.

Saiko Bat Cave

4 (1380)Tourist AttractionPoint Of InterestEstablishment

The Saiko Bat Cave, located near Lake Saiko in the Fuji Five Lakes region of Yamanashi Prefecture, is a natural lava cave formed by eruptions of Mount Fuji. The cave's origins trace back to the 864 AD eruption of Mount Fuji, when lava flows created an extensive network of underground passages in the area. This geological formation stretches approximately 350 meters in length, making it one of the more accessible lava caves in the region for visitors to explore.

The cave derives its name from the large bat population that historically inhabited the space, though fewer bats are seen today due to increased human activity and tourism. The interior maintains a consistent cool temperature year-round, typically hovering around 3 degrees Celsius, providing a stark contrast to outside conditions regardless of season. The cave's structure showcases distinctive lava formations, including rope-like patterns on the walls and ceiling that demonstrate the direction and flow of ancient molten rock.

Visitors can explore the cave through a self-guided walking route that takes approximately 15 to 20 minutes to complete. The pathway is relatively straightforward but requires some bending and careful footing due to low ceiling sections and uneven terrain. The cave interior is equipped with basic lighting, though bringing a flashlight is recommended for better visibility of the geological features. Hard hats are provided at the entrance and must be worn throughout the visit for safety.

The cave is accessible by car from central Fuji Five Lakes areas, located roughly 10 minutes by car from Lake Kawaguchi. Limited parking is available at the site. Public transportation options are limited, though some tourists combine visits with guided tours of the Aokigahara Forest, which lies nearby. Admission costs ¥300 for adults, making it an affordable addition to a Fuji Five Lakes itinerary.

What other travelers are saying about Saiko Bat Cave

Located in Aokigahara Forest near Lake Saiko, the Saiko Bat Cave is the largest lava cave formed by the eruption of Mount Fuji in 864 AD. The cave extends approximately 386 meters in total length and features several chambers and corridors with varying ceiling heights. It is part of the “Fugaku Wind Cave – Narusawa Ice Cave – Saiko Bat Cave” trio of lava tubes, all created by the same ancient lava flow. The cave’s name comes from the bats that used to inhabit it, primarily the Eastern Bent-Wing Bats. However, the population has significantly decreased due to temperature fluctuations and human activity, and the cave is now mostly a geological site rather than a wildlife habitat. Inside, visitors can observe fascinating natural formations such as lava ledges, lava shelves, and diatomite layers, which indicate the prehistoric water levels of the ancient Sea of Se-no-Umi. The cave’s temperature remains around 10°C (50°F) throughout the year, making it cool even during summer. Illuminated pathways and safety railings make the route accessible, though some passages are narrow or require bending down. The cave tour takes about 15–20 minutes, and informative signs in Japanese and English explain geological features.

Anna Krzak

Oct 16, 2025

This is the largest cave in the area, with multiple levels. There is a decent amount to see and learn about, and the free nature center attached to it makes it worth the visit. Inside the cave there is some signage in English, and some in only Japanese (no internet to translate either). There is a path that is easy and accessible, and an optional path with tunnels so small you almost have to crawl through them, which added to the fun factor for us. More importantly, this area connects to a large network of trails through Aokigahara, an enormous old-growth forest that is breathtakingly beautiful. We used this cave as the starting point, then walked through the forest to the nearby Wind Cave (about an hour walk taking our time). There are maps all around and the trails are very well maintained and easy to follow. Taken as a whole, this was a really amazing day and well worth doing.

The bat cave is really cool and it's kind of nice to be able to go in a cave on your own and walk around. Please be mindful of the bats and quiet while you're walking around. You do have to get pretty low in some spots so definitely make sure you're wearing your helmet and be prepared to maybe get on your hands and knees. It is a little cold in the cave but it's nice in the summer. There's a bus stop out front and you can easily walk to the other caves from here

A very nice cave inside a beautiful forest (actually part of Aokigahara Forest) that offers a standard route and a more difficult one. We, of course, decided to follow the more challenging one. It was worth it! We could walk over a petrified lava flow and other caves that supposedly host bats (we didn’t see any).

Worth a visit. The cave is beautiful, as is the surrounding forest. The cave path is really fun to do, but it has a very low ceiling in some areas, so requires appropriate clothing & footwear to enjoy. They provide safety helmets, but I was glad to have shoes with a grip on.

Saiko Bat Cave

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What other travelers are saying about Saiko Bat Cave

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