Yakushima is a round, mountainous island about 60 kilometres south of Kyushu, and it feels like Japan's primeval heart. The interior is dominated by ancient cedar forest — yakusugi trees, some thousands of years old, draped in moss and fern in an atmosphere so damp and green that Hayao Miyazaki reportedly used it as inspiration for Princess Mononoke. UNESCO listed the island as a World Heritage Site in 1993, the same year as Himeji Castle and Horyu-ji — recognition that this island's ecological value ranks with Japan's greatest architectural treasures.
The main draw is hiking. Jōmon Sugi, a cedar estimated at between 2,000 and 7,200 years old, requires a full day on foot to reach — roughly 22 kilometres return on a wooden boardwalk trail through increasingly spectacular forest. Easier but equally atmospheric is Shiratani Unsuikyo Ravine, a mossy wonderland in the lower forests accessible to most walkers. Above the forest, Mount Miyanoura at 1,936 metres is the highest point in Kyushu, reachable on multi-day traverses.
The island's coast offers a different world entirely. Nesting sea turtles come ashore in summer at beaches on the east coast, and the surrounding waters are good for snorkelling. The town of Miyanoura on the north coast is the main arrival point, with ferry services from Kagoshima. The other main settlement, Anbo, is smaller and quieter. The island has a well-run visitor infrastructure — trail counters, regulated access numbers on some routes, and good accommodation clustered around the port towns.
Yakushima gets extraordinary rainfall, particularly in the interior mountains. The local saying holds that it rains 35 days a month. Pack accordingly. The best time to visit for hiking is May–June and September–October; July and August bring crowds, heat, and typhoon risk.