Boyne Island is a coastal town and locality in the Gladstone Region, Queensland, Australia. In the 2021 census, the locality of Boyne Isla…Boyne Island is a coastal town and locality in the Gladstone Region, Queensland, Australia. In the 2021 census, the locality of Boyne Island had a population of 4,835 people. Boyne Island is 25 kilometres south of Gladstone.