This book constitutes the refereed proceedings of the Third International Conference on Data Science and Artificial Intelligence, DSAI 2025, held in Peradeniya, Sri Lanka, during November 19-21,2025.

The 22 full papers and 4 invited talks were included in this book were carefully reviewed and selected from 92 submissions.They were organized in topical sections as follows: Large Language Models and Advanced NLP, Computer Vision and Deep Learning for Image/Video Analysis, Healthcare, Medicine, and Survival Analysis, Time Series Forecasting and Predictive Modeling, Explainable AI and Bias Detection, Optimization, Efficiency, and Edge Computing, Domain-Specific Applications and Case Studies.