This 6-volume set LNCS 16535-16540 constitutes the proceedings of the 31st International Conference on Database Systems for Advanced Applications, DASFAA 2026, held in Jeju, South Korea, at April 27-30, 2026. The 228 full papers presented in this book were carefully reviewed and selected from 834 submissions. They cover topics such as: Search and Recommendation Index and Storage Systems Graph and Social Network Machine Learning for Database Cloud Data Management Bio and Health Informatics Data-driven AI Data Quality and Credibility Text and Data Mining Data Mining and Knowledge Discovery  Security, Privacy and Trust Information Extraction and Summarization Query Processing and Optimization RDF and Knowledge Graphs Distributed Ledger and Blockchain Industry Papers Demo Papers