The Ashmore and Cartier Islands are uninhabited Australian external territories in the Timor Sea characterized by low sandy islands, coral reefs, and surrounding shallow marine ecosystems.

📍 Ashmore and Cartier Islands are an external territory of Australia located in the eastern Indian Ocean, northwest of mainland Australia and south of Indonesia. The territory consists of two main reef systems—Ashmore Reef and Cartier Reef—with no land borders and surrounded entirely by the Indian Ocean.

The Ashmore and Cartier Islands’ geography is defined by low-lying coral reefs, small sandy cays, and shallow lagoons. The total land area is extremely small—about 5 square kilometers (1.9 square miles)—with most of the territory consisting of surrounding marine environments. The islands are flat, barely rising above sea level, and support limited vegetation such as grasses and shrubs. The surrounding waters are rich in marine biodiversity, including coral reefs, fish, and seabirds. Their remote location and fragile ecosystems have led to strict protection, making the territory important for conservation, marine research, and environmental monitoring.