Tuamarina is defined by Statistics New Zealand as a rural settlement. It covers and had an estimated population of as of with a population density of people per km2. It is part of the larger Tuamarina statistical area. Tuamarina had a population of 237 at the
2018 New Zealand census, an increase of 15 people (6.8%) since the
2013 census, and a decrease of 30 people (−11.2%) since the
2006 census. There were 87 households, comprising 117 males and 120 females, giving a sex ratio of 0.97 males per female. The median age was 45.8 years (compared with 37.4 years nationally), with 48 people (20.3%) aged under 15 years, 30 (12.7%) aged 15 to 29, 123 (51.9%) aged 30 to 64, and 39 (16.5%) aged 65 or older. Ethnicities were 94.9% European/
Pākehā, 12.7%
Māori, 2.5%
Asian, and 2.5% other ethnicities. People may identify with more than one ethnicity. Although some people chose not to answer the census's question about religious affiliation, 63.3% had no religion, 27.8% were
Christian and 1.3% had other religions. Of those at least 15 years old, 30 (15.9%) people had a bachelor's or higher degree, and 33 (17.5%) people had no formal qualifications. The median income was $41,200, compared with $31,800 nationally. 30 people (15.9%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 120 (63.5%) people were employed full-time, and 24 (12.7%) were part-time.
Tuamarina statistical area Tuamarina statistical area surrounds the settlement and also includes
Rārangi. It covers . ==Education==