This volume CCIS 2189 constitutes the refereed proceedings of the 12th Conference, JCC-BD&ET 2024, held in La Plata, Argentina during June 25-27, 2024. The 12 full papers presented were carefully reviewed and selected from 37 submissions. They were categorized under the topical sections as follows: Parallel and Distributed Computing, Machine and Deep Learning, Smart Cities and E-Government, Visualization, Emerging Topics, Innovation in Computer Science Education, Computer Security.