Tōriike, Natural monument and karst pond in Miyakojima, Japan.

Tōriike is a pair of natural karst ponds on the west coast of Shimoji Island in Miyakojima, Okinawa. The seaward Ichi-no-ike is 75 m across and 45 m deep; the inland Ni-no-ike is 55 m across and 25 m deep. They connect underground, and the seaward pool also links to the sea through a cave. The pools formed when a coastal limestone cave was eroded by waves and its roof partly collapsed, creating a doline that seawater entered.

Tōriike formed when a coastal limestone cave was enlarged by wave erosion and its roof partly collapsed, creating a doline that seawater entered. On 28 July 2006 it was designated a national Place of Scenic Beauty and Natural Monument, the first dual designation in 33 years. The designation does not restrict diving in the ponds.

Local lore gives the pools their namesake link: the sea-side pool is tied to the legend of Yonatama, a sea spirit recorded in the 1748 Miyakojima Kiji Shitsugi, and a rock called Mamako-dai near the shore recalls the stepchild tale in the 1727 Yosho Kyuki. The pools were designated a national Place of Scenic Beauty and Natural Monument on 28 July 2006, the first double designation in 33 years.

A 2002-built walkway leads from Tōriike toward the smaller Nabesoko Pond, but a 2016 typhoon damaged it and the section beyond Tōriike has been closed since. The pools themselves have no built rim or railing, so watch your footing on the uneven limestone. Diving is not restricted by the 2006 designation.

The two pools are connected underground, and the seaward pool also links to the sea through a cave, so the water level rises and falls with the tide. A thermocline makes the water appear to change color, and the varying salinity and temperature support many fish and shellfish, making the pools a diving spot.