The size distribution of plastic debris in the Mediterranean (n = 3,901 plastic items; this study) is compared to those measured for plastic accumulation regions in the open ocean (n = 4,184 plastic items; [5]). Both plastic size distributions were obtained using the same methodology. Horizontal axis shows the size limits of the bins in logarithmic scale. Because the width of the bins is not uniform, the vertical axis (i.e., normalized abundance of plastic) is shown as number of plastic items divided by the width of the bin (in millimeters). In the comparison of the plastic size distributions in Mediterranean and open-ocean waters, note the logarithmic scale of the vertical axis. The percentages (in abundance) of plastic types (pellets/granules, films, fishing threads, foam, fragments) found in the Mediterranean Sea are shown in the chart at the top right corner.