The national park lies on the southwest coast in Southern province, approximately 100km from south of Colombo. The reef at Hikkaduwa extends about 130 m seawards before dropping sharply to the soft substrate at 7-10 m. A few rocky islets are located in the nearshore area and the shoreline protection system is formed by coastal sandstone and submarine coral reefs. The area forms the Wet Zone receiving an average annual rainfall over 2000mm. The southwest monsoon period is severe on the coast and average over 280mm of rainfall during the months of mid-April to mid-June and the northeast monsoon period from mid-September through November averaging about 225 mm of rain per month. Very strong winds blow during the southwest monsoon.