Louth Bay is a settlement in South Australia. It is named after the bay named by Matthew Flinders on 26 February 1802. At the 2006 census, Louth Bay had a population of 408. Aquaculture is an important industry for Louth Bay, though fishermen and local residents are concerned about stock escapees and pollution impacts from existing operations. Concerns included algal growth and seagrass degradation, plastic pollution and the loss of amenity.
Louth Island is a large privately owned island located within Louth Bay. 3km to the south east of Louth Island lies the smaller Rabbit Island, which is part of the Lincoln National Park.