Green Island rises six hectares above sea level, the only coral cay with a rainforest canopy on the Great Barrier Reef. Formed over six thousand years from compacted coral debris, the island sits fifteen kilometres northeast of Cairns in water that averages twenty-four metres depth.
Captain Cook charted the cay in 1770 during his voyage along the Queensland coast, naming it after the astronomer Charles Green. By 1890 the island had become a beche-de-mer processing station, and in 1937 the Queensland government declared it a national park—the first reef island in Australia to receive protection.
Today Green Island functions as both a marine sanctuary and a day-visit destination, welcoming over three hundred thousand visitors annually. The surrounding reef platform extends two kilometres in diameter and supports over one hundred coral species. Brain corals form bommies three metres wide; staghorn thickets shelter parrotfish, wrasse, and juvenile barramundi cod. Visibility ranges from fifteen to thirty metres depending on tidal exchange, with the northern shore offering the calmest conditions between May and October. The fringing reef lies within swimming distance of the beach—no boat transfer required—making snorkeling Cairns Green Island tours accessible to first-time reef visitors and families with younger children.
Beneath the surface, the reef slopes from two metres at the lagoon edge to twelve metres along the outer drop-off. Green and loggerhead turtles forage on seagrass beds between coral heads. Schools of batfish hover near mooring buoys; blacktip reef sharks patrol the shallows at dawn. The reef sustains over sixty fish families, from thumbnail-sized damselfish to metre-long Maori wrasse. Glass-bottom boat tours traverse the same zones for non-swimmers, while semi-submersible craft offer hull-level viewing without entering the water. The island's rainforest interior—crossed by boardwalk trails—holds Pisonia grandis trees and nesting colonies of noddy terns, creating a terrestrial counterpoint to the marine environment.
Catamaran departures from Cairns run multiple times daily, with crossing times under fifty minutes. Most operators include snorkel equipment, reef-safe sun protection zones, and marine biologist briefings. The coral cay remains open around the clock, though commercial ferry services align with daylight hours to maximize underwater visibility and reef activity.
8 hr
