This research aims to develop an acceleration solution to improve the delayed construction project at PT Freeport Indonesia. The study integrates Critical Path Method-Program Evaluation and Review Technique (CPM-PERT) using Primavera software and Monte Carlo simulation to analyze the delayed schedule and improve project scheduling practices. These methodologies help identify critical activities, consider different time estimates, and predict the probability of multiple outcomes of the improved schedule. The study shows a 13.9% chance that the construction will be completed in 164 days, determined by the Crashing CPM-PERT method combined with the Monte Carlo simulation. The findings provide a robust framework for enhancing project scheduling practices, leading to more accurate schedule analysis and better schedule performance.