The 18th International Conference on Cross-Cultural Design, CCD 2026, held as part of the 28th International Conference on Human-Computer Interaction, HCI International 2026 (HCII 2026), took place in Montreal, QC, Canada, during July 2026. A total of 7435 individuals from academia, research institutes, industry, and government agencies from 94 countries submitted contributions to HCII 2026. Following peer review, 1463 papers and 360 posters (as short research papers) are included in the volumes of the HCII 2026 proceedings published just before the start of the conference. Three volumes (LNCS 16712, 16713, 16714) of the HCII 2026 proceedings are dedicated to this year?s edition of the CCD Affiliated Conference Area focusing on topics related to: Cross-Cultural Design (Part I): Cross-Cultural UX, Interaction and Product-Service Design; Cross-Cultural Approaches for Intelligent Systems, Mobility and Applied Interaction Design; Design for Social Innovation, Sustainability and Public Systems;  Cross-Cultural Design (Part II): Cross-Cultural AI, Generative Design and Cultural Representation; Cross-Cultural Education, Creativity and AI Literacy;  Cross-Cultural Design (Part III): Cultural Heritage, Digital Preservation and Interactive Experiences; Cross-Cultural Communication, Policy and Societal Dynamics; Cultural Impact in Human-AI Interaction and Emotional Experience.