Trekking Nakajima | An Uninhabited Island in Lake Toya

Nakajima, floating in the middle of Lake Toya, is an uninhabited island reachable only by sightseeing boat. Formed by volcanic activity about 50,000 years ago, it holds a primeval forest and some of the most special nature in the whole geopark. Walk an island in the lake and, with luck, meet wild Ezo deer—this is a trek to recommend to anyone seeking something quiet and genuine. Kamonoya, a lodging operator on Lake Toya, shows you how to enjoy trekking Nakajima.

Nakajima island floating in Lake Toya — Nakajima in Lake Toya; the largest is Oshima (“big island”) (photo: Wikimedia Commons)

Crossing to the island by sightseeing boat

You reach Nakajima on the Lake Toya sightseeing boat from the pier by the onsen town. The crossing takes about 20 minutes. Nakajima consists of Oshima (the largest island), Kannonjima, Bentenjima and Manjujima; the one you can land on and trek is Oshima.

Lake Toya sightseeing boat pier (Google Street View) — The sightseeing boat pier in the Lake Toya onsen town (image: Google Street View)

Landing is possible only in season, roughly late April to mid-November; you cannot land in winter. Schedules and fares change with the season, so check the latest on the Toyako Kisen official website.

Two trekking courses

Oshima has trails you can choose to match your fitness.

Shorter course (about 2 hours) — a relatively relaxed walk through a forest of Sakhalin spruce. Good for forest bathing.
Island loop (about 7.6 km, roughly 3 hours) — a full trek around Oshima. There are rocky sections and real walking to be done.

You must register to enter at the Forest Museum where the course begins. Before setting off, always confirm the time of the last boat and return in time for it. On an uninhabited island, managing your time matters more than anything.

Nakajima seen from the north shore of Lake Toya — The forest of Nakajima, seen from the north shore of Lake Toya (photo: Wikimedia Commons)

An island where you can meet Ezo deer

Nakajima is home to Ezo deer. A few animals brought over long ago multiplied, and many now live on the island. Walk the forest quietly and you may suddenly come across one. They are wild animals, so keep your distance and observe gently.

Notes for walking

Footing: there are rocky and uneven sections. Rather than sneakers, hiking shoes or trekking shoes are safer.
Time: as an uninhabited island, shops and vending machines are limited. Bring drinks and snacks, and be sure to make the last boat.
Season: landing is only possible in season, and boats may be suspended in bad weather.

A day trip to the island from a Lake Toya lodging

The boat pier is in the center of the onsen town, easy to reach from any Kamonoya property. We recommend crossing to the island for a morning trek and relaxing at your lodging in the afternoon. See the complete hiking guide and the practical guide for seasons and gear.

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