Proceedings of the 13th Conference on Cloud Computing, Big Data & Emerging Topics (JCC-BD&ET 2025), held in a hybrid modality (both on-site and live online settings were allowed). JCC-BD&ET 2025 was organized by the III-LIDI and the Postgraduate Office, both from School of Computer Science of the National University of La Plata.JCC-BD&ET 2025 covered the following topics: high-performance, edge and fog computing; internet of things; modelling and simulation; big and open data; machine and deep learning; smart cities; e-government; human-computer interaction; visualization; and special topics related to emerging technologies.