<p>Anthropogenic particles (AP) were assessed at 12 coastal sites in Nuevo Gulf (NG), Patagonia, Argentina, a semi-enclosed basin subject to significant human pressure. The highest average concentration of AP in coastal seawater was recorded in the Puerto Madryn (PMY) area (6.6 AP L⁻¹), nearly double that observed at the remaining nine sites farther from the urban center (3.2 AP L⁻¹). Conversely, high average concentrations of AP in intertidal sediments were widely distributed across the gulf (overall average 87.8 AP kg⁻¹ dw). The physical and chemical properties of AP were similar between matrices. Fibers were the most common shape, predominantly blue, followed by transparent and black, with an average length of 783.4&#xa0;μm. The dominant polymer types were polyethylene terephthalate, signature dye only, and anthropogenic cellulose. Puerto Madryn appears to be the primary source of AP pollution in NG, likely from textile and maritime activities. The results suggest that high-frequency wind variability disperses AP in multiple directions despite the predominant surface cyclonic gyre.</p>