The national park is situated 1 km off the coast of Nilaveli, a coastal town in Eastern Province, encompassing a total area of 471.429 hectares.

[1] The annual rainfall ranges between 1,000–1,700 millimetres (39–67 in) while most of the rain is received during the North-eastern monsoon season from October to March.

The large pigeon island's coral reef fauna is dominated by Acropora spp.

[1] Faviidae, Mussidae and Poritidae species dominate the coral reef around the rocky islets.

Uncontrolled tourism has resulted in reef degradation and loss of biodiversity and fish density.

Scientific research was hindered due to the civil war in the past two decades.