The statistical area of Whataroa-Harihari had a population of 642 at the 2018 New Zealand census, an increase of 30 people (4.9%) since the 2013 census, and a decrease of 111 people (-14.7%) since the 2006 census. There were 276 households. There were 348 males and 297 females, giving a sex ratio of 1.17 males per female. The median age was 40.7 years (compared with 37.4 years nationally), with 147 people (22.9%) aged under 15 years, 96 (15.0%) aged 15 to 29, 300 (46.7%) aged 30 to 64, and 102 (15.9%) aged 65 or older.