Plastics follow a linear economic structure, leading to detrimental environmental effects, such as global warming and ecosystem destruction, through incineration and accumulation throughout their life cycle. This study examined the types, potential generation amounts, and properties of recycled plastics from waste electrical and electronic equipment (WEEE) to assess the feasibility of the closed-loop recycling of plastics from WEEE under South Korea’s EPR system. Actual data from companies were used to determine the factors, such as the processing volume of WEEE. As of 2021, acrylonitrile-butadiene-styrene (53,363 tons), polypropylene (14,320 tons), and polystyrene (8199 tons) were the recycled plastics produced by both large and small WEEE. The properties of recycled plastics meet the specifications of new electrical and electronic products. In addition, an analysis using Life Cycle Assessment (LCA) methodology showed that the recycling effect (avoided emissions) reached 262,033 tons of CO2 eq. per year. Therefore, closed-loop recycling is the most suitable and effective method for reducing greenhouse gases. This paper presents the potential amount of recycled plastics generated from WEEE within South Korea’s regulatory framework, providing valuable foundational data for policy development for promoting the use of recycled plastics.