[Fukushima] Lake Inawashiro, the fourth largest lake in Japan

NEFT Editorial Department
2016.10.18
Last updated: 2022.02.16

Lake Inawashiro is located in the center of Fukushima Prefecture, south of Mount Aizu Bandai, often referred to as the Fuji of Aizu, and is known as the fourth largest lake in Japan. It is said that
the lake was formed as a basin by a fault around 23 million years ago, and that the lake was formed over tens of millions of years thereafter.
An eruption of Mount Bandai caused 52 surrounding villages to collapse and sink to the bottom of the lake, leaving only Okishima Island in the northwest of the lake, and a legend surrounding the formation of Okishima Island is passed down in the Aizu region.

Photo by M Murakami – R1019202 / Size-adapted.

Before the war, the lake was used for agricultural purposes, but now it's thriving as a tourist destination, with many visitors enjoying sightseeing boats and camping and barbecues on the lakeshore.
Sightseeing boats operate daily to tour Okinoshima Island, taking 35 minutes from Nagahama via Okinoshima Island. You can fully enjoy the natural beauty of nature on a lake cruise, taking in the magnificent scenery of Mt. Bandai and its majestic reflection on the lake's surface.
Tours with children can also take advantage of humorous boats, such as the swan-shaped "Hakucho Maru" and the turtle-shaped "Kame Maru."
Reservations are also accepted for Akazaki and Lake Center Tours (90-minute ride) and private chartered cruises between Nagahama and Funatsu, suitable for parties and weddings on board.

Lake Inawashiro is a relatively clear lake, with a depth of 94m at its deepest point and visibility of 12m to 13m.
The source of the Nagase River that flows into the lake is volcanic acidic water, making it an oligotrophic lake. This prevents the proliferation of underwater plants and algae, resulting in high transparency.
Nevertheless, Sphagnum moss grows in a 3m-deep section near the northern shore of Lake Inawashiro, and the "Lake Inawashiro Sphagnum Moss Community" has been designated as a national natural monument.
This area is famous as a migration site for swans, and is designated and managed by the national and prefectural governments as a protected area to protect the swan ecosystem.
Visitors to watch the swans gather on the surface of Lake Inawashiro can be seen taking videos and capturing the natural scenery with their cameras.