This six-volume set LNCS 15986-15991 constitutes the proceedings of the 30th International Conference on Database Systems for Advanced Applications, DASFAA 2025, held in Singapore, during May 26–29, 2025. The 136 full papers presented in this book together with 89 short papers were carefully reviewed and selected from 731 submissions.They cover topics such as Part I- Machine Learning and Text. Part II- Emerging Application; NLP and Spatial-Temporal. Part III- Graph; Knowledge Graph. Part IV- Database core; Fedrated Learning; Social; Steams & Time Series. Part V- Recommendation and Security & Privacy. Part VI- Language Model; Industry Papers and Demo Papers.