Carnley Harbour is a large natural harbour in the south of the Auckland Islands, a subantarctic part of the New Zealand Outlying Islands.^[1] Formed from the drowned crater of an extinct volcano, the harbour separates the mainland of Auckland Island from the smaller Adams Island.^[2] The harbour is sometimes referred to as the Adams Straits.

The harbour is undeveloped (the Auckland Islands are uninhabited), and has three major arms: North Arm, Musgrave Bay, and Western Arm. Of these, the first two are deep indentations in the coast of Auckland Island; the last connects with Victoria Passage to form a channel separating Auckland and Adams Islands.