This four-volume set LNCS 16053-16056 constitutes the refereed proceedings of the 30th European Symposium on Research in Computer Security, ESORICS 2025, held in Toulouse, France, during September 22&24, 2025. The 100 full papers presented in these proceedings were carefully reviewed and selected from 600 submissions. They were organized in topical sections as follows:  AI and Data-Centric Security, Systems and Hardware Security, Privacy, Cryptography and Secure Protocol Design, Blockchain and Financial Security, Privacy Policy and Identity Management, Adversarial and Backdoor Defenses.