Research on microplastic in coral ecosystems in Indonesia is infrequent. This research will observe Microplastic on the coral reef dive tourism in Tidung Island, Kepulauan Seribu, Jakarta Bay. The number of microplastics varied between 60 to 340 particles/kg dry weight. Fiber was the most microplastic type found in all stations; it ranged from 67% to 100%. Size of microplastic found in this study ranged <100 to >1100 𝞵𝞵m. We found four types of polymers (polybutylene, polyethylene, polypropylene, and polyester) with the highest percentage of polyethylene at 61.76%. We assume that microplastics observed in coral reef sediment on Tidung island originated mainly from anthropogenic sources. Waste management must be tightened and enhanced in the Kepulauan Seribu and neighboring areas, such as the western area of Java Island and its adjacent areas.