Biei's "Blue Pond" Complete Guide! Best Season to See the Mysterious Blue and Detailed Access Information

The "Blue Pond" (青い池, Aoi Ike), quietly nestled in Biei Town (美瑛町, Biei-chō), Kamikawa District (上川郡, Kamikawa-gun), Hokkaido (北海道), is a mystical scenic spot that, as its name suggests, holds breathtaking cobalt blue waters. It gained global recognition after being featured as a wallpaper for Apple's MacBook Pro, and has now become a popular destination attracting numerous tourists from both Japan and abroad. We will delve into how this special place came into being, what makes it so appealing, and the best ways to visit it.

The Charm and Mysterious Origins of the Blue Pond

The greatest charm of the Blue Pond is its unique water color, known as "Biei Blue" (美瑛ブルー), and the fantastical landscape created by the withered trees (larch and white birch) standing in the water. This pond, in fact, is not naturally formed; it is an artificial pond that was accidentally created during erosion control work designed to prevent volcanic mudflow disasters from Mount Tokachi (十勝岳, Tokachi-dake).

After the eruption of Mount Tokachi in 1988 (Showa 63), a concrete weir (堰堤, sekitei) was constructed on the main stream of the Biei River (美瑛川, Biei-gawa) as a disaster prevention measure. This weir dammed the waters of the Biei River, causing water to accumulate upstream and form the pond. The trees that originally grew on the riverbed became submerged, and their withered forms now create the iconic scenery of the Blue Pond.

The scientific reason why the pond water appears blue is due to components like sulfur and aluminum flowing into the Biei River water from the upstream Shirogane Onsen (白金温泉) area. These components form invisible fine particles (colloidal particles) in the water, and when sunlight hits these particles, shorter-wavelength blue light is strongly scattered and reaches our eyes. This is believed to be why the "Blue Pond" shines blue. Additionally, the sulfur and lime components in the water are said to whiten the rocks at the bottom of the pond, further enhancing its blueness.

Seasonal Expressions: Best Season and Time of Day

The Blue Pond dramatically changes its appearance depending on the season, time of day, and weather, offering a different profound impression with each visit.

Spring (April - Early June)

In early spring, around April, the pond water may appear slightly greenish due to the influence of melting snow. However, from mid-May to late June, the weather stabilizes with consecutive sunny days, making it the best season to admire the pond's most vibrant cobalt blue. During this period, when fresh greenery begins to sprout, the contrast between the Blue Pond and the surrounding nature is also beautiful, allowing visitors to enjoy a stroll in the refreshing climate.

Summer (July - August)

In summer, the strong sunlight brightly illuminates the pond's surface, making the blue color shine even more vividly. As the sun sets later, you can enjoy the cobalt blue scenery for a longer period. However, this period coincides with Hokkaido's peak tourist season, making it the busiest time. Especially on weekends in July and August, and during the Obon (お盆) holiday period, parking waits and traffic congestion on surrounding roads are expected, so planning with ample time is necessary.

Autumn (September - October)

In autumn, the surrounding larch and white birch trees begin to change color, creating a beautiful landscape with the contrast of red and yellow foliage against the blue pond. While the autumn foliage season is relatively short, the combination of the mesmerizing blue and the fiery red and yellow is a breathtaking sight worth visiting.

Winter (November - March)

During winter, the pond water freezes, and snow accumulates on top, so you cannot see the blue surface. The entire area is enveloped in a silvery-white world, and the withered trees, adorned with snow, create a completely different fantastical landscape compared to the period when the water is blue. Particularly at night, the illumination mentioned later takes place, offering a special experience where the silvery-white world is adorned with light.

Best Time of Day and Weather

If you want to see the most vibrant cobalt blue, we recommend visiting on a sunny day when the sun is high, around 1:00 PM to 2:00 PM. During this time, sunlight easily reaches the bottom of the pond, maximizing the scattering of blue light.

In the early morning (around 6:00 AM to 9:00 AM), the water surface can reflect the surrounding trees like a mirror, allowing you to enjoy a quiet and mystical atmosphere different from midday. Also, as there are relatively fewer tourists, it's recommended for those who wish to slowly savor the scenery. In the evening, it tends to be shaded, so the blueness tends to be more subdued.

Regarding weather, sunny days are when the cobalt blue appears most vibrant. On the other hand, the day after rain, increased water flow can bring in mud and sand, potentially making the pond's color lighter or cloudy, so caution is advised. It's best to aim for a visit after a period of clear weather or a few days after rain has subsided.