Green Island is a famous Great Barrier Reef coral cay known for its underwater observatory and reef setting.
The island lies about 27 kilometres northeast of Cairns and is surrounded by Green Island Reef. Visitors can view shallow marine life from an underwater observatory or through glass-bottom boats, making the reef accessible without scuba diving. Its beaches, rainforest and nearby coral habitats also make it a major tourism destination.
Green Island is sometimes confused with Fitzroy Island, which is a continental island with a different geological origin. Green Island itself is a coral cay: its land was built from accumulated reef-derived material, while its surrounding reef provides the principal marine attraction. The island is within the Great Barrier Reef Marine Park.