The conservation park consists of land described as "section 682, north out of hundreds, county of Flinders", being the entirety of Tumby Island.[3] The land first acquired protected area status as a fauna conservation reserve declared on 9 January 1969 under the Fauna Conservation Act 1964-1965.[3] On 27 April 1972, the fauna conservation reserve was reconstituted as the Tumby Island Conservation Park under the National Parks and Wildlife Act 1972.[5] On 19 December 1991, additional land was added to the conservation park to extend protection over land located between high tide and low tide.[2][6] As of 2018, it covered an area of 48 hectares (120 acres).[4]
The area under protection is considered significant for the following reason: "a small island providing feeding and roosting habitat for seabirds."[7][8]