Hawi is a census-designated place in Hawaii County, Hawaii, United States. The population was 1081 at the 2010 United States Census.Hawi is situated to the west of the community of Kapaau. Together they comprise the most densely populated region in the district of North Kohala. Historically this part of Kohala is significant as the birthplace of Kamehameha I and the location of the Moʻokini heiau in the Kohala Historical Sites State Monument. The two communities were once busy commercial centers during the operation of the Kohala Sugar plantation.Hawi is the turnaround point for the Ironman World Championship Triathlon. It is the northernmost point on the bicycle leg, where athletes return to the finish line at Kamakahonu in Kailua-Kona.