Umi Jigoku Guide: Beppu's Mystical Cobalt Blue Hell Resembling a Tropical Sea

Last updated： January 8, 2026

This article introduces Umi Jigoku, one of the 7 hells on the Beppu Hell Tour.

Umi Jigoku

Umi Jigoku (Sea Hell) is one of the 7 hells on the Beppu Hell Tour in Beppu City, Oita Prefecture, and boasts the largest scale among all the hells. The name was given because the cobalt blue surface of the water resembles the beautiful colors of the sea.

Umi Jigoku Basic Information
Item	Details
Water quality	Saline acidic spring (containing radium and ferrous sulfate)
Temperature	Approx. 98°C
Depth	200m to the hot spring source
Hours	8:00 am–5:00 pm
Closed	Open year - round
Admission	Adults (high school and above): 500 yen / Children (elementary and junior high): 250 yen
Smoking	No smoking area
Access	Car: Approx. 15 min from Beppu Station / Bus: Approx. 20 min from Beppu Station
Address	559 - 1 Kannawa, Beppu City, Oita Prefecture 874 - 0045
Phone	0977-66-0121
Official site	https://www.umijigoku.co.jp/

Umi Jigoku is located on the south side and the westernmost point of the 7 hells on the Beppu Hell Tour. It is right next to Oniishibozu Jigoku and about a 5-minute walk from Kamado Jigoku.

Map of Beppu Hell Tour showing locations and photo thumbnails of Umi Jigoku, Kamado Jigoku, Oniyama Jigoku, Shiraike Jigoku, Chinoike Jigoku, and Tatsumaki Jigoku

Brilliant Blue: Cobalt Blue Hot Spring Reminiscent of a Tropical Sea

The highlight of Umi Jigoku is undoubtedly this cobalt blue hot spring that evokes images of a tropical sea.

White steam rising from the cobalt blue hot spring and rocky area at Umi Jigoku

Despite its beauty, this is not the sea but a hot spring. The rising steam and billowing vapors are what make it a “hell.”

View of the water surface and white steam rising from the edge of the rocky area at Umi Jigoku

White steam spreading across the cobalt blue water surface bordered by black rocks

Blue hot spring pool at Umi Jigoku surrounded by black rocks and rising steam

Steam shooting up toward the blue sky and blue water surface of Umi Jigoku

The water quality of Umi Jigoku is acidic with a temperature of about 98°C. The depth to the hot spring source is over 200 meters.

The cobalt blue color of the water surface is due to the ferrous sulfate contained in the hot spring components. The highly transparent hot spring water and ferrous sulfate react with sunlight to create this mystical blue color.

Viewing Umi Jigoku from the Observation Deck

Stone-paved path leading to the observation point and signpost

Umi Jigoku also has an observation deck where you can get a bird’s eye view of the cobalt blue hell from above.

View looking down at the blue hot spring pool of Umi Jigoku and visitors from the observation deck

Blue water surface and dense steam of Umi Jigoku visible through the observation deck railing

Wide view of Umi Jigoku hot spring pool and steam rising against the green hillside from the observation deck

Akaike Jigoku: A Crimson Red Pool

At Umi Jigoku, in addition to the beautiful cobalt blue hell, you can also see the bright red Akaike Jigoku (Red Pond Hell).

Red-colored water surface of Akaike Jigoku and rocks surrounded by white steam

Crimson red water surface of Akaike Jigoku and rocky area enveloped in white steam

It is quite fascinating that hot springs of completely opposite colors exist so close to each other.

Red water surface of Akaike Jigoku and rising steam viewed from in front of the rocky area

Hakuryu Inari Okami Shrine

Right next to the cobalt blue hell stands Hakuryu Inari Okami, a shrine believed to bring blessings for household safety, business prosperity, and traffic safety.

Visitors walking through the vermillion torii gates lining the approach to Hakuryu Inari Okami Shrine

Although compact, this shrine offers a quintessentially Japanese landscape. You can also draw omikuji (fortune slips) here.

A Wide Selection of Souvenirs: From Beppu Specialties to Kyushu Products

Umi Jigoku has a shop called “Shop REN” that sells souvenirs ranging from Oita Prefecture specialties to products from all over Kyushu.

Bright interior of Shop Ren with souvenir sections lined up

The shop is clean, spacious, and stocked with a wide variety of products, including food, alcohol, juice, toys, and miscellaneous goods.

Souvenir snacks piled high along the aisles of Shop Ren

In addition to many Oita Prefecture souvenirs, you can also find souvenirs from all over Kyushu.

Oita Prefecture and Kyushu-exclusive snack souvenirs displayed at Shop Ren

Display stand with Beppu souvenirs including egg sweets and boxed confections

There is a wide selection of Beppu-exclusive sake, Oita Prefecture sake, and Kyushu sake.

Shelves of sake corner lined with Beppu-exclusive and Oita Prefecture sake and shochu

Among them, the barley shochu “Enma” is available in a Beppu-exclusive design and makes a great souvenir.

Display shelf with small bottles of Beppu-exclusive design barley shochu Enma

Local character goods are also available.

Souvenir corner with local character plush toys and miscellaneous goods

Incidentally, the most popular item is the bath salts called “Enman no Yu.”

There is also a rest area.

Rest space at Shop Ren with tables along glass windows overlooking the garden

Hell’s Famous Treat: Gokuraku Manju

Exterior of the Gokuraku Manju shop with a traditional noren curtain

Gokuraku Manju is a must-try specialty when visiting Umi Jigoku.

Sales counter of Gokuraku Manju with a traditional noren curtain

Gokuraku Manju are steamed buns made using the steam from Umi Jigoku.

Blackboard menu showing small manju and prices at Gokuraku Manju

A pack of 15 costs 650 yen. They are bite-sized and easy to eat.

Tray of small Gokuraku Manju before steaming

Gokuraku Manju packed in a clear container with bamboo skewers

Each one is small, but they have a proper manju taste. A gentle sweetness softly spreads in your mouth.

Gokuraku Manju picked up with a bamboo skewer showing the inside, with remaining manju in the pack

Japanese Scenery and Gardens

Trees and flowers are planted around Umi Jigoku. You can enjoy the charming scenery unique to Japan.

Small pond with water lilies and red-railed walkway in the Umi Jigoku garden

Information sign about tropical water lilies and round leaves with light purple flowers floating in the pond

Cherry blossoms and pond scenery against the blue sky in the Umi Jigoku garden

Tropical water lilies bloom in the garden from early May to early November. Additionally, during the Obon period in August, a “Giant Water Lily Experience” is offered for lower elementary school children (up to 20kg).

The bright red Akaike Jigoku mentioned earlier is also located in this garden.

A Boiling Sea: The Cobalt Blue Hell

Blue water surface and dense steam rising at Umi Jigoku with vermillion torii gate

Umi Jigoku is said to have been created about 1,200 years ago by an eruption of Mount Tsurumi. Even after all these years, hot water at 98°C continues to gush forth without end.