Boomer Island is a tied island in the south east region of Tasmania, Australia.

It is known for a large castle built upon it and is owned by Gunter Jaeger, a businessman.

[1][2] The landmass is Crown land from the high-water mark to 30 metres inland.

An artificial tombolo connects the landmass to the mainland in Boomer Bay, which itself lies within Blackman Bay.

The island can be seen in several public photographs.