Lake Yu (Yunoko) Hiking Guide — Nikko’s Alpine Lake Loop
Lake Yu (Yunoko, 湯ノ湖) is a small alpine lake at about 1,480 m in the Yumoto Onsen area — the highest, furthest point on the Tobu Bus route from Nikko. An easy one-hour loop circles the shore, with Nantai Mountain across the water and some of the earliest autumn colour in Nikko. Base yourself at Earth Hostel Nikko Riverhouse.
The lake sits in deciduous forest with Nantai Mountain to the south and the Shirane range set back to the northwest. The loop combines lakeside path with occasional road sections, and tame ducks patrol the shore, approaching hikers looking for food. For those finishing a Senjogahara hike at Yumoto Onsen, the Lake Yu loop is the perfect complement — an extra hour of gentle walking before the bus home, or a hot-spring bath at the Yumoto onsen inns. Lake Yu is one of more than two dozen routes mapped in our Nikko hiking guide.
Trail at a Glance
| Distance | 3.09 km loop around the lake |
| Duration | About 1 hour |
| Difficulty | Easy — Grade I (flat lakeside walk) |
| Trailhead | Yumoto Onsen bus terminal, Lake Yu shore |
| Elevation | ~1,478 m at the lake; 60 m ascent, 50 m descent over the loop |
| Trail Type | Loop |
| Best Season | Spring to late autumn (koyo late September – early October) |
| Bus Access | Tobu Bus to Yumoto Onsen (end of line) — All Nikko Pass or Yumoto Onsen Pass |
| National Park | Yes — Nikko National Park |
| Boats | Rental rowing boats available on the lake |
Stay at Earth Hostel Nikko Riverhouse — free shuttle to Tobu Nikko or (JR) Nikko Station, running multiple times daily. Lake Yu is then 60–75 minutes by bus. Pairs perfectly with Senjogahara.
Why Visit Lake Yu?
Lake Yu is the natural endpoint for one of Nikko’s most popular routes: hiking the Senjogahara boardwalk trail from Ryuzu Waterfall northward. After 2.5–5 hours on the Senjogahara plateau, arriving at Yumoto Onsen and adding a gentle loop around Lake Yu turns a great hike into a complete day. The lake offers everything the plateau doesn’t: stillness, shade, a close-up view of alpine water, and the reward of a hot-spring bath at one of the Yumoto Onsen inns when you return to the terminal.
The lake is also one of the few places in Nikko where autumn foliage reliably arrives in late September and early October — weeks before the shrine area in the valley. If you time your visit right, you can see koyo at Lake Yu while the lower elevations are still fully green, then return for a second visit when autumn colour has worked its way down to Senjogahara and Lake Chuzenji in October.
Lake Yu is also a gateway to Shirane Mountain, the highest peak in the Kanto region. The Yumoto-side trailhead sits just north of the Yumoto Camping area, a short distance from the lake — but be aware this route is washed out and rocky in places. The safer approach to Shirane starts from the tunnel trailhead, which has no public bus; we can help arrange group transport from the hostel. See our Shirane Mountain guide for the full picture on both trailheads.
Getting to Lake Yu
By bus: Take the Tobu Bus from Tobu Nikko or JR Nikko station all the way to Yumoto Onsen — the last and furthest stop on the route. Journey time: approximately 60–75 minutes from Nikko station. You will need the Yumoto Onsen Pass or the All Nikko Pass. This is the furthest point covered by the All Nikko Pass purchased at Asakusa station in Tokyo, making it a natural end-of-line destination for travellers coming from the capital.
On foot from Senjogahara: Most travellers reach Lake Yu by hiking north from Ryuzu Waterfall along the Senjogahara boardwalk trail. Arriving at Yumoto Onsen after the full trail puts you at the lake’s southern shore. The Lake Yu loop continues from there.
From Earth Hostel: Free shuttle to Tobu Nikko or (JR) Nikko Station, running multiple times daily, then the Yumoto Onsen bus. Lake Yu makes a great standalone day when combined with an early Senjogahara start. Allow a full day.
The Lake Yu Trail
The trail loops around Lake Yu in approximately one hour. The path follows the lake shore closely, mixing quiet lakeside trail with brief road sections. The character of the walk is gentle and unhurried — this is not a strenuous hike but a nature walk with very good views.
Ducks: The ducks at Lake Yu are famously tame. They approach hikers along the shore looking for food offerings. This is charming and somewhat incongruous with the wild mountain setting. Bring bread if you want a genuinely memorable wildlife moment.
Quiet pockets: Despite the short loop distance, the trail has several sections that feel genuinely remote — fallen trees, thick moss, open meadows, and sheltered alcoves where the sound of the lake water is the only thing audible. The contrast with the busier sections near the bus terminal is marked.
Nantai Mountain views: Clear views of Nantai Mountain appear across the lake from several points on the trail. From this angle and elevation, the mountain’s volcanic cone looks different from the views at Lake Chuzenji below — more immediate and imposing.
Yu Falls, the lake’s outlet: From the southern shore of Lake Yu you look down the very top of Yu Falls (湯滝, Yudaki, “waterfall of hot-spring water”) — the point where the lake’s outlet begins its drop toward Senjogahara and, eventually, Lake Chuzenji. This view down the outlet from above is one that most visitors to the falls never see.
Rental boats: Rowing boats are available to hire on the lake in season. Getting onto the water gives a completely different perspective of the surrounding mountains and forest.
Combine With: Senjogahara + Lake Yu Full Day
The classic Nikko full day: take the first morning bus to Ryuzu Waterfall. Hike the Senjogahara boardwalk trail north to Yumoto Onsen (2.5–5 hours depending on pace). Add the Lake Yu loop (1 hour). Visit the Yumoto Onsen hot-spring baths. Take the late afternoon bus back to Nikko. This is one of the best full days available in Nikko National Park, requires only one bus pass, and can be done comfortably from Earth Hostel using the free shuttle to Tobu Nikko or (JR) Nikko Station, which runs multiple times daily.
Best Season
| Season | Conditions | Notes |
|---|---|---|
| Spring | Fresh green after snowmelt; quiet; clear lake | Very few visitors. Ideal for the peaceful atmosphere the lake offers. |
| Summer | Summer green; 5–8°C cooler than Nikko town | Good season for combining with Senjogahara. Boat hire available. |
| Autumn | Peak koyo — among the earliest in Nikko (late September – early October) | Outstanding. Come 2–3 weeks before the valley shrine area for uncrowded autumn colour. |
| Late autumn | Colour fades; buses reduce; possible early snow | Check bus schedules before visiting. Snow hiking is possible in good conditions. |
| Winter | Lake may freeze; bus service reduced or suspended | Winter visits require checking bus schedules carefully. The frozen lake is beautiful but access is uncertain. |
Frequently Asked Questions
How do I get to Lake Yu from Nikko station?
Take the Tobu Bus all the way to Yumoto Onsen — the last stop, approximately 60–75 minutes from Tobu Nikko or JR Nikko station. Buy the Yumoto Onsen Pass or All Nikko Pass before departing. The lake is a short walk from the bus terminal.
Is Lake Yu the same as Yunoko?
Yes — Lake Yu, Yunoko, and Yumoto Lake all refer to the same body of water. “Yu” means hot water in Japanese, referencing the nearby hot spring (onsen). “Ko” means lake.
Can I see autumn foliage at Lake Yu?
Yes — and it arrives earlier here than anywhere else in Nikko. At about 1,480 m elevation, koyo typically peaks at Lake Yu in late September to early October, two to three weeks ahead of the shrine district at 600 m. This makes it an excellent early-autumn destination before the main Nikko koyo crowds arrive.
Is Shirane Mountain accessible from Lake Yu?
Yes, but with a caveat. The Yumoto-side trailhead is just north of the Yumoto Camping area, a short distance from the lake — however that route is washed out and rocky. The safer approach uses the tunnel trailhead, which has no public bus (we can help arrange group transport from the hostel). Read our Shirane Mountain guide for the full two-day expedition details and both trailhead options.
Are there hot springs at Yumoto Onsen?
Yes — Yumoto Onsen has several traditional ryokan (hot-spring inns) around the lake and village area. Most allow day-use bathing (higaeri nyuyoku) for a fee. After a full Senjogahara + Lake Yu day, soaking here before the bus home is the ideal way to finish.
Visit Lake Yu from Earth Hostel
Lake Yu is best experienced as part of a longer Oku-Nikko day from Earth Hostel. Our free shuttle runs multiple times daily to Tobu Nikko or (JR) Nikko Station for the first bus, and we can advise on whether to combine it with Senjogahara, Yu Falls, or a Shirane expedition. See all hiking trails in Nikko ›
Last updated: July 2026. Bus schedules to Yumoto Onsen are seasonal — verify before departing. Boat hire availability varies by season and operator.
