Lāwaʻi is a census-designated place (CDP) in Kauaʻi County in the U.S. state of Hawaiʻi. The population was 2,363 at the 2010 census, up from 1,984 at the 2000 census.
Lāwaʻi is located on the southern side of the island of Kauai at 21°55′31″N 159°30′27″W (21.925343, -159.507385). It is bordered to the west by Kalaheo and to the east by Omao. Hawaii Route 50 passes through Lawai, leading northeast 11 miles (18 km) to Lihue and west 6 miles (10 km) to Hanapepe.
According to the United States Census Bureau, the Lawai CDP has a total area of 4.2 square miles (10.8 km2), of which 4.1 square miles (10.5 km2) are land and 0.1 square miles (0.3 km2), or 2.33%, are water.
As of the census of 2000, there were 1,984 people, 711 households, and 531 families residing in the CDP. The population density was 521.7 people per square mile (201.6/km2). There were 747 housing units at an average density of 196.4 per square mile (75.9/km2). The racial makeup of the CDP was 35.4% White, 0.3% African American, 0.3% Native American, 30.8% Asian, 5.5% Pacific Islander, 1.4% from other races, and 26.4% from two or more races. Hispanic or Latino of any race were 11.8% of the population.
There were 711 households, out of which 32.2% had children under the age of 18 living with them, 60.6% were married couples living together, 9.1% had a female householder with no husband present, and 25.3% were non-families.