The island is separated from the Tasmanian mainland by the D'Entrecasteaux Channel , and its east coast lies within the Tasman Sea .
Bruny Island is a 362 - square - kilometre ( 89,000 - acre ) island located off the south - eastern coast of Tasmania , Australia .
The island is separated from the Tasmania mainland by the D'Entrecasteaux Channel , and its east coast lies within the Tasman Sea .
Bruny Island is a 362 - square - kilometre ( 89,000 - acre ) island located off the south - eastern coast of Tasmania , Australia .