Lawai is located at 21°55'18" North, 159°30'33" West (21.921667, -159.509444).
According to the United States Census Bureau, the city has a total area of 3.90 mi2 (10.10 km2). 3.80 mi2 (9.85 km2) of it is land and 0.10 mi2 (0.25 km2) of it is covered by water. The total area is 2.52% water.
Lawai is located in the Hawaii Standard Time (Hawaii ST) timezone, GMT-10:00.