Toriike, or the Toriike Ponds, is a remarkable natural landmark on Shimoji Island in Miyakojima City. The site consists of two nearly circular ponds of different sizes that appear to sit side by side above ground, yet are connected to each other underground.
The larger pond, known as the first pond, measures approximately 75 meters in diameter and 45 meters deep. The second pond is about 55 meters in diameter and 25 meters deep. Although they look like two separate bodies of water from the surface, an underground passage connects them.
The pond closer to the sea is also connected to the ocean through an underwater cave. This unusual structure is the origin of the name “Toriike,” meaning “through pond” or “connected pond.”
Because Toriike is connected to the sea, its water level rises and falls with the tides. Differences in depth also create variations in water temperature and salinity, producing a complex aquatic environment where a variety of marine organisms can live.
These unusual conditions have made Toriike a popular destination for diving. Beneath the surface, the connection between the ponds and the surrounding sea creates an underwater landscape very different from an ordinary inland pond.
The formation of Toriike began with a limestone cave that existed along the coast. Over time, waves gradually eroded and enlarged the cave. Eventually, parts of the cave ceiling collapsed, creating large sinkholes known as collapse dolines.
Seawater then entered these depressions, forming the two deep blue ponds that can be seen today. The geological processes that created Toriike are closely related to the limestone landscape characteristic of the Miyako Islands.
The area surrounding Toriike features a distinctive karst landscape known as karrenfeld, formed through the weathering and erosion of limestone. The site is also home to plants of considerable scientific value.
Because of its exceptional geological and natural features, Toriike was designated in 2006 as both a National Place of Scenic Beauty and a Natural Monument of Japan.
Several other collapse dolines can be found beyond Toriike. One of them is Nabekoko Pond, which is also believed to be connected to the sea through an underwater cave.
A walking trail once allowed visitors to explore the surrounding area, but sections of the trail were damaged by a typhoon in 2016 and are currently closed.
Toriike is far more than a pair of beautiful blue ponds. Its unusual connection to the ocean, dramatic depth, underwater caves, tidal movements, and surrounding limestone landscape make it one of the most fascinating natural sites on Miyakojima.
For travelers interested in geology, marine environments, diving, or unusual natural landscapes, Toriike offers a rare opportunity to see how the forces of the sea have shaped the limestone islands of Okinawa.
Free of charge
20 minutes drive from Sarahama Port