Golovnin Caldera — Boiling Lake & Hot Lake (Kunashir)

The water in Kipyashee Lake is the colour of poured milk shot through with cobalt — a pH of 2.2, a surface that hisses where steam vents push through, a shoreline crusted in yellow sulfur. You stand on the rim of a four-kilometre caldera that collapsed 40,000 years ago, and you remember that the Kuril Chain is alive.

What you'll do

The day starts early in Yuzhno-Kurilsk. A 4WD transfer of around 40 minutes takes us south to the forest barrier of the Kurilsky State Nature Reserve, where a ranger meets the group, checks permits, and joins us for the day. From the barrier the trail climbs gently through what looks, at first, like ordinary taiga — until you realise the understory is solid Kuril bamboo (Sasa kurilensis), waist- to chest-high, parted only by the narrow corridor of the path. Stands of Kuril rhododendron flower pink in early summer. The walk in is roughly 7 kilometres one way, two and a half to three hours at an unhurried pace.

You crest the caldera rim and the landscape inverts: a bowl five kilometres across, ringed by forested ridges, holding two lakes. The smaller is Kipyashee — Boiling Lake: 4.5 hectares, 17 metres deep, ultra-acid, fed by hydrothermal vents that send columns of steam from the shore and from a cluster of sulfurous mud pots beside the path. The larger is Goryachee — Hot Lake: 290 hectares, mineral-warm, draining quietly to the Sea of Okhotsk via the Ozernaya River. A 400-metre creek named Sernyi (Sulfur) connects the two. We spend roughly three hours in the caldera — lunch by the fumaroles, time to circle the active solfataras at a safe distance, time to feel the ground heat through the soles of your boots.

What makes it AMIST

Most operators run Golovnin as a hurried turnaround. We don't. Our guide stays with the group from the Yuzhno-Kurilsk pier to the caldera floor and back, narrating the geology — andesitic-dacitic stratovolcano, four post-caldera lava domes, a strong hydrothermal eruption recorded around 600 years before present — without losing the thread of why this matters. Lunch is hot and locally sourced: smoked Kuril chum, black bread, thermos tea. The reserve ranger is not a formality; bears fish the salmon runs of the Ozernaya in late summer and a trained second pair of eyes is non-negotiable.

Practical notes

• Duration: 6 to 8 hours door-to-door from Yuzhno-Kurilsk, depending on group pace and weather.
• Difficulty: moderate. Roughly 14 km on foot total, 250 m of vertical, no technical sections, but the bamboo trail is humid and the volcanic soil holds water for days after rain.
• Season: July to mid-September. Outside this window snow lingers on the rim and the reserve closes the trail.
• Permits: Kurilsky Reserve permits are mandatory and are arranged by AMIST 7 working days in advance. Foreign passport details required at booking.
• What to bring: waterproof hiking boots already broken in, rain shell, layers, 1.5 L water, sunhat, insect repellent. Bear spray is carried by the ranger; clients do not need to source their own.
• Group size: capped at 8 guests plus guide and ranger. No exceptions.

Why we run this

Kunashir is the working end of the Kuril Chain — four active volcanoes on a single island, less than 25 kilometres from Hokkaido, almost no tourist infrastructure. AMIST has been moving small groups through Sakhalin and the Kurils since 2001, and the Golovnin day is the one we send guests on when they ask what the islands actually feel like. We work directly with Kurilsky Reserve staff, our guides are Yuzhno-Kurilsk residents, and we cap groups so the caldera stays the loudest thing in the room.