What Is Iriomote Island? Mangroves, Waterfalls and the Iriomote Cat

Published 2026-10-04 · Sources checked 2026-10-04 · Treasure Hunting Co., Ltd.

This guide is for visitors who want to know what makes Iriomote Island unusual before they plan a trip. It uses six English pages of the Japan National Tourism Organization (JNTO), including two blog or magazine pieces that are several years old, and the English page of the Taketomi Town Tourism Association. All pages were read on 2026-10-04.

Where a source is dated, such as an interview from 2020, this guide says so.

The short answer

JNTO describes Iriomote as the largest of the Yaeyama Islands and one of the wildest places in Japan, with most of the island covered by dense, mountainous forest. It says the island is the second largest in Okinawa Prefecture after Okinawa Island itself. JNTO's page on the World Heritage region says 90 percent of Iriomote is covered by untouched subtropical forests.

A World Natural Heritage site

JNTO says Iriomote was registered as a World Natural Heritage site together with Amami Oshima, Tokunoshima and the northern part of Okinawa Island. A second JNTO news item says the announcement was made on 26 July 2021. The registered area covers 42,698 hectares in five parts across four regions. JNTO says the region covers less than 0.5 percent of Japan's land mass but has the richest biodiversity in the country.

The Iriomote cat

The island's best-known animal is the Iriomote cat. JNTO says it is a subspecies of leopard cat found only on Iriomote, which makes the island the smallest in the world to have wildcats. A JNTO blog writer calls it a nocturnal animal found nowhere else in the world but only rarely seen. In a 2020 feature, JNTO reported that the cat is listed as critically endangered by the IUCN, that numbers have been declining in part due to traffic accidents, and that only about 100 are thought to be still alive. Treat that figure as dated.

Mangroves

JNTO's blog writer says that with its subtropical climate, Iriomote has the largest mangrove forest in Japan. The association's Japanese page on cultural properties says that along 5 kilometres of the Nakama River from the mouth the mangrove forest is magnificent, and that its scale is said to be the largest in Japan. JNTO's park page describes a river cruise on the Nakama River with riverbanks covered in mangroves, where you may glimpse a crested serpent eagle.

A JNTO feature explains how to tell three mangrove species apart by their roots. Yaeyama hirugi has thin branches and pillar-like roots supporting the trunk, ohirugi has knee roots, and mehirugi has sturdy buttress roots.

Rivers and waterfalls

JNTO says that at the heart of the island are the terraced falls known as Mariyudu. You take a sightseeing boat upstream along the Urauchi River through the deep jungle and mangroves to Gunkaniwa, then walk along a path until you reach the observatory for the falls. The association says that the Urauchi is the largest river in Okinawa Prefecture, and that the Mariyudu and Kanbire falls lie upstream.

JNTO says Pinaisara Falls in the north has a drop of 55 metres, the largest of any waterfall in Okinawa Prefecture, and that the best view is from the Funaura Marine Road. A JNTO feature says one way to reach it is by kayak up the Mare River and then a trek along an unpaved road, which takes around 50 minutes to the top of the falls including a short break.

Sea and beaches

JNTO says Iriomote has some beautiful beaches. On the northern coast is Hoshizuna-no-hama, a beach whose star-shaped sands are foraminifera, the pointy husks of tiny shelled organisms. A JNTO feature says the ocean is home to more than 400 species of coral. If you dive or snorkel around the island, JNTO says there is a chance of spotting manta rays and sea turtles, and another page says mantas gather in spring and summer along the strait between Iriomote and Kohama Island.

Other rare species

The JNTO feature mentions the Yaeyama yellow-margined box turtle, which is native only to Ishigaki and Iriomote and listed as endangered, and the Sakishima grass lizard, endemic to the Yaeyama Islands. JNTO's park page says the Yaeyama palm grows only on Iriomote and Ishigaki, and that in Yonehara the palm area is a designated national natural monument with boardwalks.

Culture and the Shichi festival

Iriomote is not only nature. JNTO's park page says the Shichi Festival has been going on for over 500 years and is held in two villages of the island to pray for a plentiful harvest, with stick fighting and a lion dance. The association's event page lists related rituals in several villages.

What we could not verify, and therefore left out

• The current number of Iriomote cats.
• Entry rules for particular waterfalls, which the 2020 feature says may be tightened.
• The dates of the Shichi Festival this year.
• Opening hours of boat services on the Urauchi and Nakama rivers.

Related guides

• How Do You Get to Iriomote Island by Ferry From Ishigaki and Get Around?
• What Should You Know Before Hiking, Kayaking and Swimming on Iriomote Island?

Sources

All URLs retrieved 2026-10-04.

1. Iriomote Island (JNTO) — (largest of the Yaeyama Islands, wildcat)
2. World Heritage: Iriomote Island and neighbours (JNTO) — (forest cover, registered area, wildcat)
3. Japan's latest Natural UNESCO World Heritage site (JNTO) — (registered with Amami Oshima)
4. Amami Oshima and Tokunoshima named UNESCO Sites of World Natural Heritage (JNTO) — (26 July 2021)
5. Explore Iriomote-Ishigaki National Park (JNTO) — (rivers, falls, palm, Shichi Festival)
6. Iriomote Island and Yanbaru (JNTO, 2020) — (mangroves, falls, cat numbers)
7. A Day in the Wild in Iriomote (JNTO blog) — (largest mangrove forest, nocturnal cat)
8. Okinawa: Island Hopping (JNTO) — (manta rays)
9. Cultural properties of Taketomi Town (Taketomi Town Tourism Association, in Japanese) — (Nakama River mangroves)