Bribie Island, 34 kilometres long and 8 kilometres at its widest, is the smallest and most northerly of three major sand islands forming the coastline sheltering the northern part of Moreton Bay, Queensland. The others are Moreton Island and North Stradbroke Island. Bribie island, hugging the coastline and tapering to a long spit at its most northern point near Caloundra, is separated from the mainland by the Pumicestone Passage. A bridge from Sandstone Point on the mainland was completed in 1963. The ocean side of the island is somewhat sheltered from prevailing winds by Moreton Island and associated sand banks and has only a small surf break. The lee side is calm, with white sandy beaches in the south.
Most of the island is uninhabited national park (55.8 square kilometres) and forestry plantations. The southern end of the island has been intensively urbanised as part of the Moreton Bay Region, the main suburbs being Bongaree, Woorim, Bellara and Banksia Beach. Buckley's Hole, at the southern tip of the island, is an important bird habitat and refuge.