This two-volume set, LNCS 16238 and LNCS 16239, constitutes the proceedings of the 26th International Conference on Intelligent Data Engineering and Automated Learning, IDEAL 2025, which was held in Jaén, Spain, during November 13–15, 2025.

The 83 full papers and 12 short papers included in the proceedings were carefully reviewed and selected from 146 submissions. The core themes of IDEAL 2025 included Trustworthy Artificial Intelligence and Generative AI, Aenetic AI, LLMs, Federated Learning, Machine Learning & Deep Learning for Real-World Applications, Data Mining and Pattern Recognition, Cybersecurity, Information Retrieval and Management, and Hybrid Intelligent Systems and Agents.