Shelter Island is approximately due west of Albany, Western Australia.
It is often referred to as Muttonbird Island as well. Some consider the much smaller, low-level granite islet located immediately to the east as Muttonbird Island, but this rock does not support a flesh-footed shearwater breeding ground (mutton birds), whereas Shelter Island does. Due to Albany's early occupation by sealers and small-boat operators there are a number of confused stories relating to place names (including Jimmy Newell's/Newhill's Harbour) along this particularly dramatic stretch. The beach immediately west of Shelter Island is known as Muttonbird Beach, and is popular for swimming, surfing, fishing, and four-wheel driving. That Muttonbird Beach is adjacent to Shelter Island lends strong support to the idea Shelter Island subsumed the original Muttonbird Island name due to another story, now forgotten.
Shelter Island is approximately off-shore from Muttonbird Beach separated by a channel that has an average depth of it is regarded as a suitable open-water dive site.
The island consists of a mass of granite but has sufficient soil for plant growth and is well vegetated on top. The island supports breeding populations of flesh-footed shearwaters and little penguins as well as small populations of feral cats and black rats.
Little penguins have also been seen on the island.
The total area of the island is . It was declared a Class 1A Nature Reserve in 1973.