This study investigates the prevalence of microplastics in the sediments and commercially exploited species *Anadara tuberculosa* (black ark) and *Ucides occidentalis* (mangrove crab) in the mangrove ecosystem of Tumbes, Peru. Microplastics were detected in all samples, with an average concentration of 726 ± 396 microplastics/kg in the sediment. The mangrove crab had higher microplastic concentrations in its gills (1.9 ± 0.9 items/g) compared to its stomach (1.6 ± 1.1 items/g), and there were significant differences between species (p < 0.05) and between tissues in the crab (p < 0.01). The estimated annual intake of microplastics by the local population from consuming these species is 431 items per capita. The findings highlight the widespread contamination of the mangrove ecosystem with microplastics, posing a concern for the marine food web and food security. The study also discusses the potential health risks associated with microplastic exposure, including oxidative stress, gene expression changes, and the presence of pathogens and pollutants.This study investigates the prevalence of microplastics in the sediments and commercially exploited species *Anadara tuberculosa* (black ark) and *Ucides occidentalis* (mangrove crab) in the mangrove ecosystem of Tumbes, Peru. Microplastics were detected in all samples, with an average concentration of 726 ± 396 microplastics/kg in the sediment. The mangrove crab had higher microplastic concentrations in its gills (1.9 ± 0.9 items/g) compared to its stomach (1.6 ± 1.1 items/g), and there were significant differences between species (p < 0.05) and between tissues in the crab (p < 0.01). The estimated annual intake of microplastics by the local population from consuming these species is 431 items per capita. The findings highlight the widespread contamination of the mangrove ecosystem with microplastics, posing a concern for the marine food web and food security. The study also discusses the potential health risks associated with microplastic exposure, including oxidative stress, gene expression changes, and the presence of pathogens and pollutants.