Microplastics (MPs) are discovered in various places even encroaching on marine protected areas (MPA). Karimunjawa National Park (KNP) is a national conservation area. The aim of this research is to investigate the occurrences of MPs pollutant in MPA and Non-MPA in KNP. The results showed that MPs from sea surface water were higher in MPA than non-MPA with range as 47.89–106.20 items/L, dominated by fragment, 1-50 µm size, black color and HDPE, LDPE, PP, Nylon, PVC, ABS, and PET in polymer types. It induced since it supplied from it surrounding, specifically the south of MPA, whereas there have been cottage constructions generating many marine debris. These findings indicate that occurrence of MPs still dominantly influenced from anthropogenic activity. However, the hydrodynamic and MPs characteristic as well play an important role in MPs distributions.