Plastic accumulation in coastal areas is a worldwide concern and Peruvian beaches are not exceptions. We visited three sandy beaches in Lima, Peru in spring 2019 and summer 2020, those were San Pedro, Costa Azul, and Las Conchitas. We collected sand to test microplastics (MP) occurrence and characterization. Fragments and fibers were the most common particle, FTIR spectrometry indicated evidence of polypropylene and polyethylene of low and high-density. The abundance of MP was not the same in the three beaches; San Pedro presented the lowest abundance and Costa Azul the highest. MP occurred in both seasons, however, there was a decrease in summer, among the three beaches, the reduction in Costa Azul was not significant. MP decrease in summer is vinculated by cleaning campaigns to welcome visitors for the summer season. However, that procedure seems not relevant in Costa Azul because maintained a high pollution level. Synergy with other human activities occurs, like fisheries in San Pedro and Las Conchitas and informal dumps in Costa Azul. Our research describes the pollution of microplastics in three important and crowded beaches during summer. Our information provides a baseline about the beach condition mainly related to microplastic pollution and the effectiveness of environmental measures like cleaning campaigns.