Iriomote is the second-largest island in Japan's Ryukyu chain — and almost entirely wild. Some 90 percent of its land is covered by subtropical rainforest, mangrove swamps, and river valleys that feel genuinely remote. The island is home to the Iriomote cat, a critically endangered wild cat found nowhere else on earth, which is why the whole island is designated a national park.
Getting around means paddling mangrove rivers by kayak — the Urauchi and Nakama are the classics — hiking jungle trails to waterfalls like Mariudo and Pinaisara, and snorkelling in clear water over healthy coral. The main settlements — Uehara and Ohara — are tiny; tourism infrastructure exists but is modest. This is not a beach resort, though Hoshizuna and the much wilder Ida no Hama reward the effort of getting there.
The island is reached by ferry from Ishigaki, which is the practical base for the whole Yaeyama group. A day trip from Ishigaki is feasible, but staying a night or two lets you explore the interior properly.