This study aims to develop a real-time mobile application-based production line balancing tool for export garment factories in Thailand, addressing the challenges posed by significant market demand. Thailand’s garment factories export OEM sportswear outfits to Europe, America and Japan, adapting products to meet ever-changing fashion trends. Consequently, production and delivery times are significantly shorter than traditional seasonal fashion cycles. Making changes to color and sizing throughout the season puts even tighter constraints on production schedules. Therefore, the manufacturer that can most swiftly adapt to fluctuating demands for the combination of colors, sizes, and styles will capture the largest market share. The case study of sport ware outfit manufacturer is considered. The plant is experiencing decreased productivity resulting from suboptimal line configurations and the ongoing learning curve of the workforce. Overloaded tasks or worker skill gaps can create bottlenecks that slow down overall production. The engineering team conducted an analysis to pinpoint the specific process or resource causing the production slowdown. This analysis involved a line balancing process using stopwatch timing and spreadsheet calculations to determine the time consumption of each process step. The results were visualized in a bar graph format know as a Yamazumi chart. Subsequently, reducing the total time represented by all bars in the Yamazumi chart is necessary to achieve the desired overall time reduction. To replace manual stopwatches and spreadsheet-based line balancing, we developed a digital mobile tool equipped with an algorithm for automated line balancing analysis. Our real-time mobile tool drastically reduces the time to analyzing line balancing operation from four hours to under ten minutes. Bottleneck elimination resulted in a substantial boost to production efficiency, increasing it from 70.4% to 76.3%. This represents a notable5.9% improvement