The bay was first explored and given the name "Tumby Bay" by Captain Matthew Flinders in 1802. It was named after a parish in Lincolnshire, England. In 1840 Governor Gawler renamed the bay "Harvey('s) Bay" after one other district's early settlers. Then on 15 November 1900 the town of "Tumby" was proclaimed by Governor Tennyson, and the name of the bay was changed to "Tumby Bay". On 14 June 1984 the town officially became known as "Tumby Bay".