The island is separated from the Tasmanian mainland by the D'Entrecasteaux Channel, and its east coast lies within the Tasman Sea.

[3] On 11 March 1773, Tobias Furneaux was the first British explorer to reach the island, and anchored at Adventure Bay (named after his ship) for four days;[4] four years later on 26 January 1777 James Cook's two ships, the Resolution and Discovery stayed in the bay area for two days.

Alexander Imlay applied for a site as a whaling station at Cloudy Bay in 1837, and Brown and Rogers did the same in 1842.

[9] Even though "Cooktown"[citation needed] was marked on maps as early as the 1840s, the island was not officially opened up to European settlement until the late 1800s when the timber industry took off.

In more recent history the Bruny Island was the site of a land transfer by the state government to local Aboriginal people.

While the seaward side of the island features two long beaches—Adventure Bay and Cloudy Bay—it is for the most part extremely rugged, with cliffs of dolerite over 200 metres (660 ft) AHD in altitude.

Bruny's channel side is more sheltered and a favourite fishing and recreational boating area for local and interstate visitors.

The d'Entrecastaux Channel region, sheltered by Bruny Island, is increasingly subject to foreshore erosion.

Bruny Island is classified by BirdLife International as an Important Bird Area because it supports the world's largest population of the endangered forty-spotted pardalote, up to a third of the world population of the swift parrot, all 12 of Tasmania's endemic bird species, and up to 240,000 breeding pairs of the short-tailed shearwater (or Tasmanian muttonbird).

[16] In March 2021, awareness increased concerning the feral cat population on the island, which had been steadily growing over the last decade.

Initial findings suggest the feral cats migrated from the Eastern Shore of Tasmania, namely the Howrah/Tranmere region.

[citation needed] A key contributor to Bruny Island's economy is its growing tourism industry.

Being home to the South Bruny National Park, tourism on the island centres on the showcase of its natural assets.

[23] There are a growing number of tourism businesses on the island including a cheese factory, oyster farm, vineyard, smoke-house, lighthouse, museum, art gallery, two eco-cruises along with various accommodation properties and cafes.