East Hokkaido · TeshikagaNo.729★★Open in map →

Sunayu

— The dig-your-own beach bath on Lake Kussharo

onsenOff the trail — and worth it

A grey sand beach on Lake Kussharo where hot water rises straight through the ground. Dig a hollow with your hands and it becomes a bath; the sand is free, open at any hour, and warm enough that this strip never freezes.

FromKushiro Station
~8 hr 55 min loopAkan Bus sightseeing coach, Apr–Dec
Get off atSunayu, Lake Kussharo (Akan Bus Pirika-go)
On foot
Sunayu

Directions ↗

The sweet spot

Sunayu is on every regional itinerary and the coach parties stop here, so the beach is not a secret. What limits the numbers is the road: no scheduled local bus serves this shore, and the operator's route list runs elsewhere, to the station and the town on one side and the Wakoto peninsula on the other. Almost everyone here arrived by car or on a booked coach, which is a filter of a different kind.

Where it is

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What to look for — in walking order

Whooper swans at SunayuK.F. / CC BY-SA 3.0

The Sunayu car parkthe arrival point at the head of the beach, shared with the rest house
Retara Chip rest housethe shorefront hall for food, souvenirs and swan-boat hire
The dug pools on the sandhand-scooped hollows near the waterline, refilling from below
The unfrozen strip of shoreopen water in midwinter where whooper swans gather to keep warm
Nakajima out on the lakethe wooded island filling the middle distance from the beach

How to actually get there

Kushiro Station bus terminal → Sunayu (Akan Bus Pirika-go, booked in advance).
Cross the car park to the rest house and borrow or buy a scoop if you have not brought one.
Dig a hollow near the waterline and let it fill from below.
Walk the shore for the swans in winter, or take a swan boat out in the green season.

Akan Bus Pirika-go from Kushiro Station: The Pirika-go sightseeing coach leaves the bus terminal beside Kushiro Station and runs a single day loop through Lake Mashu, Mount Io, Lake Kussharo and Lake Akan before returning, eight hours and fifty-five minutes in all. Sunayu is the Kussharo stop and the coach holds there for twenty minutes. It runs daily from 18 April to 20 December, and seats must be booked in advance.
Leaving Sunayu: The coach carries you on to Lake Akan and back to Kushiro on the same ticket, priced at six thousand yen for an adult on the Kushiro-to-Kushiro loop. If you step off the tour here you are arranging your own way out, because the shore has no scheduled service of its own.

Directions from my location (Google Maps) ↗

About the place

Kussharo is the largest caldera lake in Japan, a ring of water fifty-seven kilometres round sitting at a hundred and twenty-one metres above the sea. Volcanic heat still leaks into it from below, and at Sunayu it reaches the surface through a grey sand beach on the eastern shore. The water that fills a hand-dug hollow is a sodium bicarbonate spring, the same class as the pools further round the lake, and it arrives at bathing temperature without anyone plumbing it. Out on the water sits Nakajima, an island of 5.7 square kilometres with twelve kilometres of shoreline of its own.

How to enjoy it

Come in the green season and the sand is a shallow bath you build yourself; come between December and March and it becomes a bird hide, because the whooper swans that fly in from Siberia crowd onto the one stretch of water the heat keeps open. The rest house opens in the morning and closes in the late afternoon, so an afternoon arrival still catches both. Bring a towel and something to dig with, and expect wet clothes either way.

Background & history

The lake fills a caldera left by an eruption long before any of this had a name, and the Ainu called the outflow Kutcharo, the throat, for the point where the water leaves for the Kushiro River. Heat has never stopped moving through the ground here: springs surface all around the shore, some of them piped, some of them left as open-air pools, and Sunayu is the version that was never built at all. The wider basin was taken into Akan-Mashu National Park, and the beach is managed from Teshikaga town rather than by any operator.

Before you go

Cash: The beach is free and there is nothing to pay to dig. The rest house on the sand takes payment for food, souvenirs and swan-boat hire in the green season, and it does accept cards.
Good to know: The beach has no closing time and no rest day, but the rest house keeps shorter hours than the shore does, opening in the morning and shutting in the late afternoon, an hour later in July and August. In deep winter the lake freezes right across and ridges of pressure ice build up on it; the Ainu museum along the shore closes for the season.
Another way: The nearest station is Kawayu-Onsen on the JR Semmo Line, from which the road runs west around the shore; hire a car or take a taxi from there, as no bus covers the last stretch. Cycle hire is available in Teshikaga through the tourism association and local operators.
After you get off: The car park and the rest house stand together at the top of the beach, and the sand starts a few steps below them. Walk to the waterline before you dig, because the hot water is under the wet sand rather than the dry.