Microplastics (MPs) are pervasive environmental contaminants even in remote and pristine locations. Despite extensive literature documenting their widespread presence in marine environments, there is limited understanding of MP contamination in Marine Protected Areas (MPAs), particularly in developing countries. This study assessed MP contamination using multiple filter-feeding bivalve species as sentinels. Samplings were performed during 2022, in ten selected no-take MPAs under different management categories according to the International Union for Conservation of Nature. MPs size, shape, color, and polymeric composition were analyzed using established protocols, including Fourier Transform Infrared (FTIR) spectroscopy. MPs concentrations (0.42 ± 0.34 [0.17-2.00] particles.g