Shilang & the Big Mushroom Coral

Off Green Island's southwest coast, the Shilang dive area slopes from a gentle coral shelf — where generations of Taiwanese take their first scuba dives — into sand channels and small drop offs fed by the warm Kuroshio Current. Its landmark is the 'Big Mushroom' (Da Xianggu), a single living Porites coral colony estimated at over 1,000 years old. Once a standing pillar about 10 m tall, it was knocked onto its side by Typhoon Meranti in 2016 and now lies roughly 12 m high and 31 m long on the 18 m seabed about 150 m offshore, still growing. Green sea turtles graze the hard coral year round, parrotfish and unicornfish school over the reef, and scalloped hammerheads pass the island's exposed points in winter. A seahorse shaped underwater postbox sits in the shallows.