Marion Bay is a rural / residential locality in the local government area (LGA) of Sorell in the South-east LGA region of Tasmania. The locality is about 27 kilometres (17 mi) east of the town of Sorell. The 2016 census recorded a population of 72 for the state suburb of Marion Bay.Marion Bay is also a large bay on the south-east coast of Tasmania. Its south-western shore is contained by the Marion Bay Important Bird Area.