1. Hoshino Resorts TOMAMU Unkai Terrace (Hokkaido)
2. Hottarakashi Onsen (Yamanashi)
3. Takabocchi Highlands (Nagano)
4. Echizen Ono Castle (Fukui)
5. Takeda Castle Ruins (Hyogo)
6. Bitchu Matsuyama Castle (Okayama)
7. Kunimigaoka (Miyazaki)

Sea of clouds, or “unkai” in Japanese, is a special phenomenon that can only be seen in certain places under the right conditions. In Japan, there are several “unkai” spots that are gaining attention, such as at Takeda Castle Ruins (known as the “Japanese Machu Picchu”) and Takabocchi Highland, a spot with magnificent views. Here are 7 sites where you can see the see of clouds phenomenon.

What is the sea of clouds?

The sea of clouds when you can see a layer of clouds from above, with the clouds creating a sea-like view. There is said to be six different types of seas of clouds, such as one where the ground lowers the temperature of the water vapor in the air.

Conditions for the sea of clouds

For the sea of clouds to appear, there are some conditions that must be met. First of all, they only appear in mountainous regions and basins. The region must also have a significant temperature difference between mornings and nights. Finally then, the sea of clouds can be seen between daybreak and early morning.

If there is little to no wind, high humidity and clear skies, then the sea of clouds should look its best. These conditions are usually met during the spring and autumn months.

When visiting “unkai” locations, make sure to check the weather beforehand and on the day of.

Safety precautions

When going “unkai” seeing, make sure to layer up. You will have to be outside in high altitudes early in the morning, so it can get pretty cold.

When walking to the viewing spots, it might still be dark outside. If that’s the case, make sure to bring a headlight or a flashlight with you.

1. Hoshino Resorts TOMAMU Unkai Terrace (Hokkaido)

Hoshino Resorts TOMAMU locates in the Yufutsu District of Hokkaido. It is about a 90 minute drive from New Chitose Airport. On the hotel grounds, you can find the Unkai Terrace, located 1,088 meters above sea level. From here, you can see three different types of seas of clouds.


Taiheiyo-san Unkai (credit: Hoshino Resorts TOMAMU)

The first is the Taiheiyo-san Unkai (太平洋産雲海), or the Pacific Ocean Sea of Clouds. This is where the fog from the Pacific Ocean drifts on inland. This type of “unkai” has a unique, flowy structure, and has a dynamic look to it.


Tomamu-san Unkai (credit: Hoshino Resorts TOMAMU)

The second is the Tomamu-san Unkai. It is created when cold air is collected in Tomamu’s basin. On some days, you can see the Tomamu The Tower hotel peeking out from the sea of clouds.


Akutenkou-gata Unkai (credit: Hoshino Resorts TOMAMU)

The third is the Akutenko-gata Unkai, or the Bad Weather Sea of Clouds. As the name suggests, this sea of cloud can be seen before or after bad weather. If the weather is too unstable, then there is a chance that Unkai Terrace itself will be buried in clouds.

Cloud Pool

Cloud Pool (Credit: Hoshino Resorts TOMAMU)

The Cloud Pool at Hoshino Resorts TOMAMU opened in September 2017. It locates 8 meters above the ground, and is a cloud-shaped hammock that makes you feel as if you’re floating with the clouds.

You can check out this unkai tracker to see the weather forecasts and “unkai” appearance rates for the next day.

Getting to Unkai Terrace

To get to Unkai Terrace, you must take a gondola.

If you are staying at Hoshino Resorts TOMAMU, then you can take the hotel bus to Unkai Gondola Sanroku Station (foothill station) and head on up from there.

During the early morning hours, there are no trains or busses in operation. If you are not staying at Hoshino Resorts TOMAMU or any nearby hotels, you can go to the gondola station by car.

2. Hottarakashi Onsen (Yamanashi)


Hottarakashi Onsen

Hottarakashi Onsen in the city of Yamanashi has some breathtaking views. There are to rotemburo (outdoor baths), and one of them, the Acchi-no-yu, is open from one hour before sunrise.


Sea of clouds at Hottarakashi Onsen

The sea of clouds at Hottarakashi Onsen has a gorgeous orange glow, due to the sunrise hitting the clouds. Behind it, you can see Mount Fuji. The view of the sea of clouds and Mount Fuji from the rotemburo is indeed a luxury.

Getting to Hottarakashi Onsen

Since you would need to be at Hottarakashi Onsen before sunrise to see the sea of clouds, it is recommended that you go by car (since public transportation does not operate at those hours). From both the Katsunuma Interchange and the Ichinomiya Misaka Interchange to Hottarakashi Onsen is about a 25-minute drive.

3. Takabocchi Highlands (Nagano)


Takabocchi Highlands

Takabocchi Highlands, located in Nagano prefecture, offers an amazing view of Lake Suwa and the Japanese Alps from 1,665 meters above ground level. The name “Takabocchi” comes from the legend of the Japanese mountain giant, Daidarabocchi, which is said to be resting on these highlands.

Takabocchi-Kogen-Sea-of Clouds-and-Mount-Fuji

The sea of clouds and Suwa’s early morning lights

You can see the sea of clouds together with Mount Fuji at Takabocchi Highlands. Above the clouds is a view of Mount Fuji and the Japanese Alps, and below the clouds is a view of the city of Suwa and its morning lights.

On lucky days, you can see the sea of clouds tinted in orange from the sunrise. This view of the orange clouds and the Japanese alps is one that is unique to Takabocchi Highlands.

The best season to catch the sea of clouds at Takabocchi is between September and March. Head to the highlands between daybreak and early morning to see the sea of clouds.

Getting to Takabocchi Highlands

The best way to get to Takabocchi Highlands is by car. Busses only run on rare occasions, and there are usually no ways to get there via public transportation.

You can park your car at the Second Parking Lot. From there to the top of Takabocchi Highlands is about a 10-minute walk.

4. Echizen Ono Castle (Fukui)


Echizen Ono Castle

Echizen Ono Castle locates in Fukui prefecture’s city of Ono, and locates 249 meters above ground level on Kameyama Hill. The castle was built in 1576 by Kanamori Nagachika, who was given land in Ono by Oda Nobunaga, the ruling military commander at the time.


Echizen Ono Castle and the sea of clouds

The sea of clouds at Echizen Ono castle surrounds the entirety of Kameyama Hill, making it look like a castle in the sky. You can catch this magnificent view from Inuyama Castle’s southern demaru (fortress), locating about 1 kilometer west of Echizen Ono Castle. To the demaru is about a 30-minute hike, so make sure to wear comfortable clothes and shoes.

The best season to see the sea of clouds at Echizen Ono Castle is between October and late February. In particular, November is the best month for it. Get there between dawn and 9a.m. to try to catch the view. The sea of clouds at Echizen Ono Castle only appears about 10 times a year, so those who see it are extremely lucky!

Getting to Echizen Ono Castle’s viewing spot (Inuyama Castle)

There are three different hiking routes to get to Inuyama Castle, which locates 324 meters above ground level. The easiest course is the Kuwakake Course, since there are no turns or confusing paths.

Head to the foot of the hill by car, since there are no public transportation options available early in the morning. You can park your car in the hardware store parking lot near the foot of the hill.

5. Takeda Castle Ruins (Hyogo)


Takeda Castle Ruins

Takeda Castle Ruins, nicknamed “Japan’s Machu Picchu”, locates in Hyogo prefecture’s city of Asago. It sits on the top of Mount Kojo, and is sometimes referred to as “Torafusu-jo 虎臥城”, since the shape of it resembles a tiger (tora 虎) lying down (fusu 臥す).

You can see the sea of clouds surrounding Takeda Castle Ruins from inside and outside the castle.


The view from the castle

You can see the sea of clouds from the castle ruins. The clouds surround the area, and you will feel as if you are floating in a sea of clouds.


The view from Ritsuun Gorge

Catch this magnificent view of Takeda Castle Ruins floating in the sky from Ritsuun Gorge. The sea of clouds at Takeda Castle Ruins can be seen between October and November between dawn and 8:30a.m.

Getting to Takeda Castle Ruins and Ritsuun Gorge

To get to both locations, you must hike up a hill. From the parking lot by the foot of the hill to Takeda Castle Ruins is about a 50-minute walk. To Ritsuun Gorge from the Ritsuun Gorge parking lot is about a 40-minute walk.

Since there are no public transportation options available during the early morning hours, getting there by car is the best choice. Also, keep in mind that Takeda Castle Ruins has opening and closing hours, and it is off limits during its closed hours.

6. Bitchu Matsuyama Castle (Okayama)


Bitchu Matsuyama Castle

Bitchu Matsuyama Castle, located in the city of Takahashi in Okayama prefecture, is known as one of Japan’s Three Famous Mountain Castles. This is the only mountain castle in Japan with a castle keep remaining in tact, and is registered as a national important cultural property.


The sea of clouds surrounding Bitchu Matsuyama Castle

Bitchu Matsuyama Castle is sometimes referred to as the “mountain castle in the sky”, due to this brilliant view. This view can be seen from the Bitchu Matsuyama Castle Observatory, located 1 kilometer away from the castle. In the autumn seasons, you can see the sea of clouds and the fall foliage at the same time.

There are wild monkeys living in the woods by the observatory. If you see one, don’t get too close to them and be careful.

The sea of clouds at Bitchu Matsuyama Castle can be seen between late September and early April. The chances are especially high between late October and early December.

Getting to Bitchu Matsuyama Castle Observatory

The Bitchu Matsuyama Castle Observatory locates a 1-minute walk from a parking lot, so going by car is a convenient option. Also, for a limited time during the sea of clouds season, there is a special taxi running from JR Bitchu-Takahashi Station.

7. Kunimigaoka (Miyazaki)

Kunimigaoka is a 513-meter tall hill locating in the city of Takachiho in Miyazaki prefecture. According to legend, this is where Takeiwatatsu-no-mikoto, the grandson of Emperor Jimmu (Japan’s first emperor according to legend), visited this hill and gazed at his land.


Kunimigaoka’s sea of clouds

The view from the hill is phenomenal, and it even received one star on the 2011 Michelin Green Guide Japan. You can see the sea of clouds surround the Takachiho Basin with the mountains in the background. The sight is divine and one that you will never forget.

The best season to see the sea of clouds is between late September and early November. A few times a year, you can catch the sunrise hit the sea of clouds for a beautiful orange tint.

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Miyazaki < Takachiho

Kunimigaoka at sunrise

A Mystical Sea of Clouds Awaits Atop Kunimigaoka Hill (Miyazaki Prefecture) Kunimigaoka in Takachiho, Miyazaki Prefecture has a gorgeous Michelin-star view, and expansive sea of clouds from autumn to winter. This article tells you when and how to see the sea of clouds, and nearby tourism information.


Getting to Kunimigaoka

There is a parking lot just a minute walk away from the parking lot at Kunimigaoka. You can drive there and walk to the observatory.

There is also a special tour, named the “Un-dameshi Goraiko Tour”, during the season. If you stay at an accommodation in the town of Takachiho, you can participate in the tour. You can learn more about the tour here (in Japanese): 雲だめしご来光ツアー

Make use of the “Unkai NAVI”!

Seeing an “unkai” largely depends on the weather conditions of that day. Check out this “Unkai NAVI” website, that calculates the probability of “unkai” appearances at major sea of cloud destinations throughout Japan!