
Kusatsu Onsen Trips Get Even Better! 7 Special Experiences in the Yamba Dam Area
Centered on Yamba Dam, completed in 2020, and Lake Yamba-Agatsuma, which glows an emerald green, the Yamba area offers a wide variety of activities.
In addition to the historic hot spring town of Kawarayu Onsen, roadside stations and lakeside parks are scattered along the shore, making it enjoyable for both day trips and overnight stays.
The lakeside resort born alongside the dam is also perfect for a drive from the Tokyo metropolitan area or a trip paired with Kusatsu Onsen.
What Is Yamba Dam?
Located in Naganohara-machi, Gunma, Yamba Dam is a concrete gravity dam built on the Agatsuma River, about 116 m high and about 291 m long.
After resident relocations, plan revisions due to a change of national government, and other developments, it finally began management operations in spring 2020.
Today, a lakeside resort surrounded by rich nature spreads out around Yamba Dam and Lake Yamba-Agatsuma, which was created by the dam.
Around the lake, campsites, parks, and roadside stations have been developed, making it ideal for driving and cycling.
In addition to water activities such as canoeing, kayaking, and SUP (stand-up paddleboarding), you can also enjoy unique experiences like bungee jumping into the lake and riding an amphibious bus.
Downstream from the dam, activities such as hiking in the nationally designated scenic spot Agatsumakyo Gorge and riding a pedal-powered rail trolley on the former JR Agatsuma Line track bed are especially popular.

At Naruhodo! Yamba Museum on the dam grounds, the history and mechanisms of dam construction are introduced in an easy-to-understand way.
At Yamba Tenmei Mudflow Museum, you can see archaeological remains from the Jomon period through the Edo period that were discovered during excavations related to the construction work.
This is an area where you can enjoy large-scale views of the dam and lake, a wide range of activities set in great nature, and fascinating history all at once.

The History and Role of Yamba Dam
Built on the Agatsuma River in Naganohara-machi, Gunma, Yamba Dam is a multipurpose dam that handles flood control and helps ensure a stable supply of tap water and industrial water for the Tokyo metropolitan area.
The plan began after major flood damage struck the Tone River basin due to Typhoon Kathleen in 1947.
As the metropolitan area population increased and land subsidence caused by groundwater pumping became more serious, the need for the Yamba Dam plan to balance flood control and water use grew.
Meanwhile, the planned inundation area concentrated nationally designated scenic sites, hot spring areas, residential communities, and vital infrastructure such as railways and national highways, and opposition movements prolonged due to relocation issues and impacts on tourism.
After project reviews and even a declaration of cancellation associated with a change of national government, it became a long-term project that took 68 years from planning to completion.
In October 2019, during Typhoon No. 19, Yamba Dam, which was in trial impoundment, drew attention for having reduced downstream damage, and in 2020 it finally began full-scale operation.
As a concrete gravity dam about 116 m high, it serves the purposes of flood control, supplying tap water and industrial water to the metropolitan area, maintaining the normal functions of the Agatsuma River, and power generation.
Access to Yamba Dam
Access from Kusatsu Onsen to Yamba Dam
There are two ways to get from Kusatsu Onsen to Yamba Dam.
The first is a route using a scheduled route bus operated by JR Bus Kanto.
Route buses run at roughly one bus per hour, traveling from Kusatsu Onsen Bus Terminal to Naganohara-Kusatsuguchi Station.
From Naganohara-Kusatsuguchi Station, take the Yamba Gururin loop bus or a taxi to Yamba Dam.
The second is to use the Yamba Gururin loop bus from Kusatsu.
The first service bound for the dam departs from Kusatsu Now Resort Hotel, stops at Kusatsu Onsen Bus Terminal, then heads to Naganohara-Kusatsuguchi Station and various bus stops in the Yamba area.
The last service runs the reverse route and operates to Kusatsu Onsen.
Only one bus per direction extends the route to Kusatsu, but it can be a very convenient option if the timing works.
Route 1
- Access
-
1. Travel from Kusatsu Onsen Bus Terminal to Naganohara-Kusatsuguchi Station by JR Bus Kanto.
2. After getting off, walk a few minutes to the bus stop Naganohara-Kusatsuguchi Station Side <Dts Headquarters>.
3. Board the Yamba Gururin loop bus (bound for the Yamba Dam area) from Naganohara-Kusatsuguchi Station Side <Dts Headquarters>, get off at Yamba Dam, and arrive. - Time Required
- About 1 hour 5 to 10 minutes.
- Fare
- 780 yen (JR Bus Kanto) + 400 yen (Yamba Gururin).
Route 2
- Access
- Travel from Kusatsu Onsen Bus Terminal to Yamba Dam by the Yamba Gururin loop bus and arrive.
- Time Required
- About 45 minutes.
- Fare
- 800 yen (Yamba Gururin).
Access from the Tokyo Area
From the Tokyo area, you can access Yamba Dam by rail or highway bus. Choose the easiest route based on your itinerary and the loop bus timetable.
Route 1 (By Train)
- Access
-
1. Take the shinkansen from JR Tokyo Station to JR Takasaki Station
2. Transfer at JR Takasaki Station to a local train on the Agatsuma Line and ride to JR Kawarayu-Onsen Station
3. Take the Yamba Gururin loop bus from Kawarayu-Onsen Station and get off at Yamba Dam. - Time Required
- About 3 hours 40 minutes.
- Fare
- 5,920 yen (JR ticket and reserved-seat limited express ticket) + 400 yen (Yamba Gururin).
Route 2 (By Highway Bus)
- Access
-
1. Take the highway bus “Joshu Yumeguri-go” from Busta Shinjuku (Shinjuku Station New South Exit) to Kawarayu-Onsen Station
2. Take the Yamba Gururin loop bus from Kawarayu-Onsen Station and get off at Yamba Dam. - Time Required
- About 4 hours 20 minutes.
- Fare
- 3,200 to 3,600 yen (Joshu Yumeguri-go) + 400 yen (Yamba Gururin).
7 Special Experiences Around Yamba Dam and Its Surroundings
Around Yamba Dam, there is a wide range of experiences that let you enjoy a special time.
Here, we will introduce seven carefully selected experiences.
Together with these special experiences around Yamba Dam, enjoy Yamba Dam to the fullest.
1. Amphibious Bus Tour: Yamba Nyagaten-go
Let’s tour the sparkling blue waters of Lake Yamba-Agatsuma on the colorful red-and-white amphibious bus called Yamba Nyagaten-go.
Departing from Yamba Mizunoeiki Maruiwa, the bus drives along the lakeside road with views of the great nature of the Yamba area, and there is also guiding narration by Tengu no Ten-chan, featured on the Yamba Nyagaten-go design.
As the bus approaches the water, it is finally time for the highlight, the splash-in.
The amphibious bus charges down a dedicated ramp straight into the water, sending up an intense burst of spray.
While cruising leisurely on the lake, take in the spectacular views of Yamba Dam and the surrounding mountains as seen from the water.
Before or after the tour, enjoy gourmet options such as dam curry and sweets at Yamba Mizunoeiki Maruiwa. There are also services that depart from and arrive at the bus stop Naganohara-Kusatsuguchi Station Side <Dts Headquarters>, so choose what fits your travel itinerary.

Basic Information
- Japanese Name
- 水陸両用バス 八ッ場にゃがてん号ツアー
- Postal Code
- 377-1303
- Address
- Yamba Mizunoeiki Maruiwa, 904-3 Yokokabe, Naganohara-machi, Agatsuma-gun, Gunma
- Phone
- 0279-82-5596 (Yamba Mizunoeiki Maruiwa)
- Budget
- 2,800 yen for junior high school students and older, 1,820 yen for elementary school students and younger
- Official Website
- Official Website
2. Agatsumakyo Gorge Rail Bike Agattan
Running downstream from Yamba Dam, “Agatsumakyo Gorge Rail Bike Agattan” is a pedal-powered rail trolley attraction that travels along a section of the former JR Agatsuma Line track bed, partly rerouted due to dam construction.
With the clatter of the rail joints-gattan, gattan-you proceed along a one-way track of about 2.4 km laid on the north side of Agatsumakyo Gorge, a nationally designated scenic spot.
Along the way, you will encounter Tarusawa Tunnel, once known as Japan’s shortest railway tunnel, small rail crossings, and a series of peaceful landscapes woven by the gorge’s nature and rural scenery.
Highlights include sections looking down into the gorge and the illuminated interior of the tunnel.
The route continues from below Yamba Dam to the opposite bank of Agatsumakyo Roadside Station, so it is also recommended to combine it with hiking in Agatsumakyo Gorge.

Basic Information
- Japanese Name
- 吾妻峡レールバイク アガッタン
- Postal Code
-
Karigasawa Station: 377-0814
Agatsumakyo-Yamba Station: 377-1301 - Address
-
Karigasawa Station: Higashiagatsuma-machi Agatsumakyo Area Promotion Center, 868-1 Matsutani, Higashiagatsuma-machi, Agatsuma-gun, Gunma
Agatsumakyo-Yamba Station: Below the left side of the Yamba Dam main body, 1121-31 Kawarahata, Naganohara-machi, Agatsuma-gun, Gunma - Phone
- 0279-26-9431 (Agatsumakyo Gorge Rail Bike)
- Budget
-
A one-way ride for a 3-seater costs 3,000 yen, and a round trip costs 5,000 yen.
A one-way ride for a 4-seater costs 3,500 yen, and a round trip costs 6,000 yen. - Official Website
- Official Website
3. Yamba Bungee
Of the three bridges spanning Lake Yamba-Agatsuma, the 494 m-long Yamba Ohashi Bridge is the closest to the dam.
In a wide-open location with sweeping views of the dam body and surrounding mountain ridgelines, you can experience bungee jumping.
Dive in a straight line from a jump platform about 45 m high toward the emerald-green lake surface.
Another attraction is the chance to try styles not found at other sites, such as Water Touch, where you can touch the water, Tandem Jump, where two people jump at the same time, and Wheelchair Bungee, which wheelchair users can also experience.
In 2026, it is scheduled to be held in July, when the lake water level is lower. Make a refreshing dive toward the vivid lake under the summer sky.

Basic Information
- Japanese Name
- 八ッ場バンジー
- Postal Code
- 377-1301
- Address
- Yamba Ohashi Bridge, Kawarayu, Naganohara-machi, Agatsuma-gun, Gunma
- Phone
- 0278-72-8133 (reservations only)
- Budget
- 13,000 yen per jump, 6,000 yen for a second jump on the same day, Water Touch 24,000 yen, Tandem Jump 28,000 yen, Wheelchair Bungee 13,000 yen
4. Canoe and Kayak Experiences
On Lake Yamba-Agatsuma, canoe and kayak tours are offered, including Canadian canoes that allow children to ride in the same craft.
Let’s take a waterside stroll on the calm lake surface, which changes its expression depending on the season and water level.
On either tour, you can look up at Fudo Falls from the lake surface or paddle out into forest scenery that feels like a jungle.
Because courses are guided according to the day’s weather and conditions as well as participants’ skill levels, beginners can join with confidence.
Highlights of the Canoe Tour
This is an approximately two-hour tour that moves leisurely across Lake Yamba-Agatsuma in a stable Canadian canoe, receiving instruction from a guide.
Because it seats two to three people, children can ride in the same craft, and since it tends to get you less wet than a kayak, you can relax and fully enjoy the quiet scenery of the surrounding mountains and dam lake.
It is also recommended for outdoor beginners and families with children.

*If a child can wear the smallest life jacket size, canoe experiences are possible from ages 4-5.
Highlights of the Kayak Tour
Compared with a canoe, a kayak lets you experience Lake Yamba-Agatsuma from a viewpoint closer to the water surface.
Paddle a one- to two-person kayak at your own pace and head out with a sense of adventure beneath suspension bridges and toward the emerald-green lake surface (also known as Yamba Green), the dam body, and more.
Because a kayak turns easily, it is also nice that you can get closer to coves and rock walls.

Introducing the Organization and Facility Running the Tours|Paddle-ya
Paddle-ya is a JSPA (Japan Safety Paddling Association) certified school.
It offers canoe, kayak, and SUP (stand-up paddleboarding) tours on Lake Yamba-Agatsuma.
The departure point for the tours is “Yamba Hayashi Furusato Park,” located at the base of Fudo Ohashi Bridge.
Because participation requirements and tour times vary by tour, check the official Paddle-ya website for details.

For other activity and gourmet information around Lake Yamba-Agatsuma, check Kawarayu Onsen Asobi no Kichi NOA.
5. Viewing Fudo Falls
Viewable from Fudo Ohashi Bridge, Fudo Falls is a graceful waterfall that drops about 90 m into the lake. The water volume is not especially large throughout the year, and a thin white waterfall runs down the black cliff of Fudozawa. In addition to being visible straight ahead from a viewpoint on the bridge, you can also go close to the waterfall from the lake surface via the canoe and kayak tours and SUP mentioned above.
In the depths of winter, the frozen waterfall shines like a three-tiered blue-white ice object. This magnificent icefall has become a new seasonal tradition of the Yamba area from January to February.

6. Agatsumakyo Gorge Hiking
Spreading downstream from Yamba Dam, Agatsumakyo Gorge is a V-shaped canyon, a nationally designated scenic spot, carved over many years as the Agatsuma River cut through lava from volcanic eruptions.
From the open area beyond the dam body elevator, a fantastic landscape continues along the river for about 2.5 km to “Fureai Ohashi,” with cliffs and strange rock formations lining both sides and a cobalt-blue flow sparkling below.
Highlights include “Haccho Kuragari,” where at the narrowest point the river is about 3 m wide and about 50 m deep, and “Shikatobi Bridge,” where a vermilion arch stands out against the gorge’s greenery.
With the dam behind you, a well-maintained promenade continues along the left bank, while an unpaved hiking course continues along the right bank to Shikatobi Bridge, and from either side you can enjoy superb views looking down into the gorge.
Walking one way from Yamba Dam to Fureai Ohashi takes about one hour, and if you use Yamba Dam as your base, it is also recommended to turn back at Shikatobi Bridge and return.
If you walk all the way to Fureai Ohashi, you can return to Yamba Dam by the rail bike Agattan, or you can keep walking to Agatsumakyo Roadside Station and soothe your fatigue at a day-use hot spring.

Mid to late April, when mitsuba-tsutsuji azaleas color the area, May with dazzling fresh greenery, and late October to early November, when autumn leaves deepen in color, are the times when Agatsumakyo Gorge is at its most beautiful.
Maples, kunugi oaks, and red pines color both sides of the gorge, and on the promenade and at Shikatobi Bridge you can enjoy tunnels of fresh greenery or autumn leaves.

7. Ninja Experience at Agatsumakyo Roadside Station
Located downstream from Yamba Dam, Agatsumakyo Roadside Station is the gateway to Agatsumakyo Gorge, a nationally designated scenic spot.
On its spacious grounds, it includes the day-use hot spring Agatsumakyo Onsen Tengu no Yu, a farmers’ market, places to eat, a natural-grass dog run, and Agatsuma Fureai Park, making it a great place to spend time at a relaxed pace.
This is a roadside station with a ninja theme, rare even nationwide.
Starting with the frozen sweet “Hyorogan Kuzu Bar,” which is fun for its chewy and lightly crunchy texture, it is packed with ninja-motif foods, goods, and more.
On weekends, ninja experience events are held with the theme of the Sanada ninja who were active during the Sengoku period with bases in Shinano Province and Kozuke Province.
Especially popular is the shuriken throwing experience with prizes.
This is a unique roadside station where you can feel the world of the Agatsuma Sanada ninja through play and sweets.

Basic Information
- Japanese Name
- AGATSUMA SANADA NINJYA World
- Postal Code
- 377-0813
- Address
- Agatsumakyo Roadside Station, 6441 Mishima, Higashiagatsuma-machi, Agatsuma-gun, Gunma
- Phone
- 0279-67-3193
- Budget
- Shuriken throwing: 500 yen per try (you can throw five shuriken)
- Official Website
- Official Website
3 Gourmet Picks to Enjoy Around Yamba Dam
Around Yamba Dam, local gourmet spots are scattered where you can enjoy regional flavors along with lake scenery.
From the playful Yamba Dam Curry modeled after the dam, to craft beer unique to Kawarayu Onsen, to sweets at a cafe with lake views, here are three gourmet finds you can only encounter here.
1. Yamba Shokudo: “Yamba Dam Curry”
Twelve minutes from Yamba Dam by the Yamba Gururin loop bus, “Yamba Furusato-kan Roadside Station” sits at the base of Fudo Ohashi Bridge.
It is a popular roadside station visited not only by tourists but also by locals seeking freshly harvested vegetables.
At “Yamba Shokudo” inside the facility, you can casually enjoy local curry and regional dishes while looking out at the lake through the windows.
Starting with the specialty “Yamba Dam Curry,” there is a lineup of menus that make use of local ingredients and Yamba character, including Gunma’s sauce hirekatsu-don (rice bowl), Yamba Otsumi Dango, udon, and soba.
The signature menu here is “Yamba Dam Curry.”
It is a dish served with roux and rice on a custom partitioned plate modeled after the dam.
There are two types, a spicy version with locally grown maitake mushrooms and a mild version packed with chunky vegetables, and when you order, you also receive an original dam card available only here.

2. Sasayu Cafe: Craft Beer from Kawarayu Onsen Jozo-sha
Eight minutes from Yamba Dam by the Yamba Gururin loop bus, and just a one-minute walk from JR Kawarayu-Onsen Station, Kawarayu Onsen Asobi no Kichi NOA is a multi-purpose outdoor tourism facility in a great location.
On weekends, you can enjoy bring-your-own camping and day-use BBQ, and it also includes the free-flowing hot spring Sasayu and a cafe using milk from local Toyota Dairy, making it a place to spend time while looking out at the lake.
Kawarayu Onsen Jozo-sha inside the facility is a small craft beer brewery.
You can enjoy craft beer unique to Kawarayu, brewed with local water and bottled with the yeast sealed inside, and you can savor it at Sasayu Cafe or at the campsite.
You can also view the brewery through glass and buy bottled beer as a souvenir.

3. Yamba Mizunoeiki Maruiwa: “Imonblanc Soft”
Twenty minutes from Yamba Dam by the Yamba Gururin loop bus, Yamba Mizunoeiki Maruiwa is located at the base of Maruiwa Ohashi Bridge.
From its retro building that recreates the former Naganohara town hall, you can take in sweeping views of the lake and the grand surrounding nature.
Inside, there is a dining hall, cafe, and shop, and it is also used as the departure and arrival point for the amphibious bus.
The dining hall’s signature menu is “Maruiwa Curry,” a hamburger steak curry inspired by Maruiwa, the symbol of Naganohara-machi.
At the scenic Maruiwa Cafe, which opened in July 2025, you can enjoy “Imonblanc Soft,” made generously with the sweet potato Silk Sweet from Tommy Farm.
With rich, milky soft-serve topped with plenty of smooth sweet potato paste, this original sweet is perfect to enjoy while looking out at the lake.

Staying Overnight Near Yamba Dam Is Also Recommended! Enjoy Famous Hot Springs at Kawarayu Onsen
Six minutes from Yamba Dam by the Yamba Gururin loop bus and just a short walk from the bus stop Oyu, Kawarayu Onsen is a lakeside hot spring town.
The former hot spring town sank beneath the lake due to the completion of Yamba Dam, and today it has been reborn on higher ground overlooking the lake as a small lakeside hot spring destination.
Centered on the public bath Oyu, it is an old-yet-new hot spring town with six inns gathered together.
The colorless, transparent water carries a faint sulfur scent and feels gentle on the skin.
Even if you soak for a long time, it is less likely to leave you feeling bath fatigue.
Its history is said to be old, and it is believed to have been discovered in 1193 by Minamoto no Yoritomo when he came here on a hunt.
It has long been loved as a finishing bath to stop by after Kusatsu Onsen’s strong waters.

One recommended place to stay is the long-established “Yamakikan,” founded in 1661.
With only eight rooms on a site of about 2,000 tsubo (roughly 6,600 square meters), it features an atmospheric space with an irori hearth and old tools, surrounded by relocated traditional houses.
With a lakeside open-air bath and nostalgic kamado cooking, you can spend a luxurious time.

Located in the hot spring town’s closest spot to the dam, “Yamata Ryokan” is a small inn limited to two groups per day.
It is proud of meals made with fresh vegetables harvested from its own farm, and the handmade tableware used for hospitality also conveys warmth. In the adjacent workshop, you can also experience pottery making.

With a lineup of inns each offering its own character, you will want to choose one that fits your travel purpose and the way you want to spend your time.
4 Events Held at Yamba Dam and Around the Area
In the Yamba area and Naganohara-machi, festivals and events you will not want to miss are held from spring through autumn, starting with the winter Yukake Festival.
From a heroic naked festival where hot water spray dances in subzero mornings, to a stair climbing race up the dam steps in early autumn, to Yamba Day when summer fireworks color the lake surface, and the intense Asama Highland Snowball Fight, here are four events that captivate visitors.
1. Yukake Festival
Held every year on January 20, the Yukake Festival at Kawarayu Onsen is a naked festival in which young men wearing fundoshi loincloths splash each other with hot spring water on the coldest day of the year, giving thanks to the hot spring deity.
The water-splashing at dawn, carried out in the bitter cold amid rising steam, is truly impressive.
It is considered one of Japan’s unusual festivals.
The Yukake Festival begins at Oyu, the public bath, with Shinto rites at 5:00 am.
After a ceremony praying in gratitude to the hot spring deity and for health, safety, and well-being, young men in red-and-white headbands and fundoshi begin splashing hot water all at once.
Wrapped in steam, with spirited shouts as hot water flies through the air, the dynamic scene is well worth seeing.
Watching is free.
Photography is allowed, so be considerate of etiquette when taking pictures.
Because the festival starts just after 5:00 am, it is best to stay in Kawarayu Onsen the night before.
Because it is below freezing, do not forget warm clothing and cold-weather protection.

2. Stair Climbing Race: Yamba Dam Stair Climbing Race
In September, a stair climbing event is held at Yamba Dam, about 116 m high and now a symbol of Naganohara-machi, Gunma.
The huge dam body’s emergency staircase is specially opened, and it becomes a time-trial race in which you sprint up the dam stairs in one burst, with the stair section measuring 79 m and 316 steps within the 116 m height.
Because participation is set by level according to your preference at entry, even lower elementary school students can join.
There are a Single Attack, a one-run format, and a Double Attack, in which you compete on the combined time of two runs, and entry opens from late May on the official website with a first-come limit of 250 participants.
Check the official website for participation fees, cautions, and competition rules.
Elite athletes’ races are also held at the same time, and you can watch top-level performances in Japan.
Because it is a large event, if you hope to stay overnight, book accommodations early.
Do not forget to get your body used to it with training in advance.

3. Yamba Day
Inspired by “8 (ya) 8 (ba),” this is a local event day held around August 8 each year.
“Marutto Yamba Festival” is held with Yamba Dam, the lake area, and roadside stations as venues.
Marutto Yamba Festival
The main event is fireworks launched over the lake, with big blooms coloring the sky above the water.
With Fudo Ohashi Bridge as the main venue, it is held from evening into night on the day.
On the day, Fudo Ohashi Bridge becomes a pedestrian-only zone and is lively with food trucks and tents.
Because crowds increase during fireworks and at night, move with extra time in your schedule.
A daytime stamp rally is also held to tour nearby facilities such as Yamba Furusato-kan Roadside Station, Kawarayu Onsen Asobi no Kichi NOA, Yamba Tea House, Yamba Tenmei Mudflow Museum, and Yamba Mizunoeiki Maruiwa.
If you clear the checkpoints, you can receive a present.
Various events and services are planned at each facility.

4. Kita-Karuizawa Festival of Fire
In Kita-Karuizawa near the border with Nagano Prefecture, this is a winter tradition where candles light up the snowfield.
About 2,000 candles are lined up across a pure white snowfield, wrapping the entire venue in a fantastical glow.
In addition to candle art where patterns emerge as the night deepens, winter fireworks launched into the freezing sky are also a highlight.
Food trucks line the venue, and it is also nice to enjoy warm food while sitting by a bonfire.


Summary
The Yamba area is a lakeside resort packed with activities, gourmet experiences, hot springs, and events, set against the grand stage of a massive dam and an emerald-green lake.
Here, we introduced special experiences unique to Yamba.
With convenient access from Kusatsu Onsen and so many attractions you cannot do them all in a single day, discover new travel charms in the Yamba area.
