Airborne microplastics smaller than 5 mm in diameter can be easily inhaled by humans, impacting their health. Human exposure to microplastics can occur in indoor environments, and this study investigates the degree of indoor deposition of microplastics in settled dust. We assessed the relationship between the number of occupants/people and the amount of microplastics in their indoor environment by determining indoor microplastic exposure in two offices, two schools, and two apartments in Surabaya, Indonesia. The settled dust was collected using a vacuum cleaner for 10 minutes on a single weekday and the weekend at each study location. The results show that the amount of microplastics collected at each location during workdays exceeded the amount found on weekends. The two offices sampled were found to have the greatest amounts of microplastics (334 particles on a weekday, 242 particles on a weekend; and 351 particles on a weekday, 252 particles on a weekend), and the two apartments produced the least amounts of microplastics (133 particles on a weekday, 127 particles on a weekend; and 108 particles on a weekday, 95 particles on a weekend). The dominant microplastic shape was that of fiber, and the dominant size range of the microplastics collected was 3000–3500 µm. The amount of indoor microplastics is influenced by activities and the number of occupants/people in the space. The exposure levels indicated here will inform environmental health policy recommendations.