The Antarctic tundra, dominated by non-vascular photoautotrophs (NVP) like mosses and lichens, serves as an important habitat for sea animals. These animals contribute organic matter and oceanic sulfur to land, potentially influencing sulfur transformations. Here, we measured carbonyl sulfide (OCS) fluxes from the Antarctic tundra and linked them to soil biochemical properties. Results revealed that the NVP-dominated upland tundra acted as an OCS sink (−0.97 ± 0.57 pmol m⁻² s⁻¹), driven by NVP and OCS-metabolizing enzymes from soil microbes (e.g., Acidobacteria, Verrucomicrobia, and Chloroflexi). In contrast, tundra within sea animal colonies exhibited OCS emissions up to 1.35 ± 0.38 pmol m⁻² s⁻¹, resulting from the introduction of organosulfur compounds that stimulated concurrent OCS production. Furthermore, sea animal colonization likely influenced OCS-metabolizing microbial communities and further promoted OCS production. Overall, this study highlighted the role of sea animal activities in shaping the soil-atmospheric exchange of OCS through interacting with soil chemical properties and microbial compositions.