Microplastics are a global ubiquitous problem, which is becoming a major issue of concern at scientific and political levels around the world. This study presents physical and chemical characterizations of microplastic debris and a comparison between the spatial distribution and anthropogenic activities in 4 Panamanian beaches located in both sides of the Isthmus. Two of them (Juan Diaz and San Carlos beaches) are located toward the Pacific Ocean, Panamá Province, whereas the others (Palenque and Punta Galeta beaches) are located at the Caribbean Sea, Colón Province. They were chosen to show different landscape management and environmental impacts: touristic and protected areas; coastal areas that receive pollutants and marine litter from urban rivers or are used for local fishing activities. Plastic debris samples were collected and visually analyzed following the protocol proposed by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP). The physical characterization of the samples consisted in the determination of variables associated with the number of plastic particles, shape, color, and size. The characterization of the polymers was performed by the attenuated total reflectance-Fourier transform infrared spectroscopy technique. A high concentration of microplastics (353 items/m2) were found at the studied sites at the Caribbean coast, whereas a lesser concentration with a greater diversity of shapes and polymer categories were found at the Pacific Coast (187 items/m2). The results indicate that, in addition to anthropogenic activities, the proximity to Panama Canal installations, as well as seasonality, natural phenomena, winds, and ocean currents may be influencing the increase in microplastic contents and the types of polymers observed.