Tumby Bay is a coastal town situated on the Spencer Gulf, on the eastern coast of Eyre Peninsula in South Australia, 45 km north of Port Lincoln. The town of Tumby Bay is the major population centre of the District Council of Tumby Bay, and the centre of an agricultural district farming cereal crops and sheep, as well as having established fishing and tourism industries.
Tumby Bay lies on the large, sheltered bay of the same name on the western side of Spencer Gulf. Much of the land surrounding Tumby Bay is used for agriculture. The coast is predominantly white, sandy beaches, on which the town itelf is situated, as well as towering cliffs to the south.
Inside the bay, Tumby Island is the only island but further offshore lie the Sir Joseph Banks Group, a small archipelago that is easily accessed by boat from Tumby Bay.
Like much of coastal South Australia, Tumby Bay experiences a Mediterranean climate with warm to hot summers and moderately wet winters.