The degradation of surfaces and its possible dependence on shape, size, and elemental composition of plastic particles were subjected. The surfaces of 146 microplastics were classified from smooth to fully eroded (%) by SEM/EDS. Structural elements and various additives were found on microplastics depending on their shapes. The surface of plastic items > 100 µm in length showed a relatively more eroded area than smaller ones, regardless of their shapes. Depending on shape, the percentage of surface erosion of irregularly shaped fragments < 100 µm was significantly enhanced compared to microbeads of the same size. These results may provide insights into assessing potential risks posed by microplastics and improve our understanding of the role of these parameters concerning possible adverse health effects on the environment. Display omitted •Relationship of MPs' degraded surface with predictors of surface erosion is studied.•Surfaces of 146 MPs were classified from smooth to fully eroded (%) by SEM/EDS.•Structural elements and many additives were found on MPs depending on their shapes.•MPs > 100 µm possessed more eroded area than smaller ones, regardless of their shape.•Surface erosion (%) of fragments was enhanced compared to microbeads, both < 100 µm.