This research explores, for the first time, the use of plastic waste to enhance the mechanical properties of Tunis soft clay, a soil known for its low stability. Soil samples mixed with 2%, 5%, and 7% plastic waste were subjected to pre-consolidation tests up to 80 kPa, followed by unloading. The results show a significant reduction in consolidation time and void ratio, along with an increase in undrained cohesion. The optimal percentage of 5%, higher than the commonly reported 4%, provides notable improvements for applications in foundations and embankments. This study opens new perspectives for better plastic waste management while offering an innovative solution to geotechnical challenges. However, further studies on implementation techniques, such as deep compaction, are needed to validate its practical application.