DemographicsCairns Bay is approximately 2.71 square kilometres. In 2016 the population of Cairns Bay was 76. The population is 59% male and 41% female. On average the monthly mortgage repayments in Cairns Bay are $450 to $599. The most common weekly income bracket is $300 to $399 per week. Weekly rents in the area are on average $200 to $224.