Zao: The Crater Lake, Summit Trails & Acid Springs — 2 Days

The Zao Ropeway climbs in two stages from the onsen village to the Jizo summit station at around 1,660 metres — the same cable cars that in winter glide between the icebound snow monsters, here carrying you up into cool alpine air and long views over the Yamagata basin. At the top, a short walk leads to the great stone Jizo statue, half-buried and serene, that gives the station its name, and on a clear day you can follow the easy ridge path toward the Kumano-dake high point and look down on the volcanic terrain. In late June and July the slopes below the summit bloom with pink komakusa, the 'queen of alpine flowers'. It is the quickest way onto the high mountain and a fine, lung-filling start to the day before the baths.

Open daily roughly 08:30-17:00; a round trip to the summit station runs around ¥3,800 (approx., 2026). The summit line has occasional maintenance closures (around May 7-29 in 2026 — confirm). From Zao Onsen village; bring a windproof layer. Allow about 2.5 hours including the ridge walk.

Zao claims to be a birthplace of jingisukan, 'Genghis Khan' barbecue — slices of mutton and lamb grilled over a domed cast-iron plate with vegetables sliding down the sides to catch the juices — and Robata, a long-running grill house in the onsen village, is the local favourite for it. You cook your own over the hot dome at the table, with a choice of cuts and a tangy dipping sauce, alongside local beer or sake. The room is plain and convivial, full of skiers in winter and hikers in summer. After a morning on the ropeway it is exactly the hearty, smoky, distinctly Zao lunch you will want before an afternoon of bathing. Other grills in the village serve it too, but Robata is the dependable choice.

Open for lunch and dinner (hours vary by season; confirm the day); jingisukan runs around ¥2,000-4,000 per person (approx., 2026). In the Zao Onsen village, walkable from the ropeway base. Allow about an hour.

The signature soak at Zao is the Dai-rotenburo, a series of large open-air baths terraced down a forested mountain stream at the edge of the village, the men's and women's pools big enough for dozens of bathers among the rocks and trees. The water is the famous Zao sulfur spring — cloudy, pale blue-white, strongly acidic at around pH 1.3 to 1.6, and so rich it leaves the skin soft and tingling, traditionally said to make you beautiful. Sitting in the hot pool with the cold stream rushing past and the forest closing overhead is the essential Zao experience, best in the late afternoon. It is open only in the warm season, which is why this route is a green-season one; in winter the village's indoor baths take its place.

Open roughly mid-April to mid-November only (closed in winter); around ¥700 (approx., 2026). At the edge of Zao Onsen village along the stream, a short walk or shuttle from the centre. Bring your own towel. Allow about an hour.

Back in the heart of the village, Kawarayu is one of Zao Onsen's three historic public bathhouses, a small, plain wooden building where the same acid spring rises right through the floorboards into the tubs — about as direct a connection to the source as a bath gets. It is hot, simple and used by locals, the unvarnished counterpoint to the big open-air baths, and costs only a few coins. Around it the old onsen lanes climb past steaming channels, the Sake-no-kami onsen shrine, and shops selling the local sulfur-spring cosmetics and onsen-steamed eggs. A short wander here, with the smell of sulfur in the air, gives you the working town behind the resort before you settle in for the night.

Open daily with limited hours; a few hundred yen honesty fee (around ¥200-300, approx., 2026); simple facilities, bring your own towel and soap. In central Zao Onsen village. The acid water can sting cuts and tarnishes silver — leave jewellery off. Allow about 45 minutes.

Among the long-established inns of Zao Onsen, the Oomiya is a comfortable, traditional ryokan with its own baths fed by the village's sulfur spring, including cypress-wood tubs where you can soak again after dinner without leaving the building. Rooms are tatami in the old style, dinner is a spread of Yamagata mountain food, and the welcome is the unhurried kind that suits a spa town. Staying in the onsen village, rather than driving in for the day, lets you bathe in the famous water morning and evening and have the quiet lanes to yourself once the day visitors go. It is the practical and pleasant base for this two-day route, and a short walk from the ropeway, baths and grills of day one.

A night with two meals runs roughly ¥15,000-30,000 per person depending on room and season (approx., 2026); higher in ski season. Book ahead in winter and autumn-leaf periods. In central Zao Onsen village. Settle in and take an evening soak. Allow the evening.

A different cable car from yesterday's, the Zao Chuo Ropeway climbs from the village to the Torikabuto station, from where short forest trails lead to Dokkonuma, a small, deep, jewel-green pond cupped in the mountainside at around 1,300 metres. The water is astonishingly clear and still, ringed by beech and conifer, and a gentle loop of boardwalk and path takes you around it and on to other little marshes and viewpoints — an easy, pretty morning walk with none of the exposure of the high ridge. Wildflowers fill the clearings in summer and the colour is superb in autumn. It is the soft, green counterpart to the stark crater lake you will see next, and a good leg-stretch before the drive up the Echo Line.

The Chuo Ropeway runs daily roughly 08:30-17:00 in season; a round trip runs around ¥1,500 (approx., 2026). From Zao Onsen village. The marsh trails are best in the green and autumn seasons. Allow about 90 minutes.

The Okama is the great set piece of Zao: a near-perfect circular crater lake about 360 metres across, cradled between the bare volcanic peaks of Goshiki-dake, Katta-dake and Uma-no-se on the Yamagata-Miyagi border. Its water, heavy with minerals and with no outlet, glows an intense emerald-to-turquoise that shifts with the light and the angle of the sun, ringed by stark grey-and-rust crater walls with no vegetation — a genuinely otherworldly sight after the green marshes below. You reach it by driving the Zao Echo Line up to the Katta pass and the short toll Highline to the rim, then walking a few minutes to the viewpoints; energetic visitors can hike the ridge. The whole road is snow-closed in winter, so this is a warm-season sight, and it clouds over fast — go early and hope for clear air.

Accessible roughly late April to early November only (the Echo Line is snow-closed in winter; early-season night closures apply). The viewpoint is free; the Highline toll is small. The summit area is cold and windy and clouds quickly — bring warm, windproof layers and go in the morning. Allow about an hour.

Right at the rim above the Okama, the summit rest house is the only place to eat and warm up on the mountaintop, and the natural lunch stop after the crater lake. It is a large, plain mountain canteen serving simple hot food — ramen, curry rice, soba, the local 'gensui' spring-water dishes and softcream — with big windows and a rooftop deck looking out over the Okama and the surrounding peaks when the cloud lifts. There is a shop for souvenirs and the Katta-dake shrine is a short walk along the ridge above. After the cold summit air a hot bowl here is welcome, and the view from the deck, on a clear day, is the last and best look at the crater before the drive back down the Echo Line. A practical, scenic end to the route.

Open in the warm season roughly 09:00-16:00 when the road is open (closed in winter); meals run around ¥800-1,500 (approx., 2026). At the Okama viewpoint above the Zao Highline. Allow about an hour.