The 2025 IUVA Asia-Pacific Regional Symposium, co-hosted by the Environmental Engineering Society of Singapore (EESS), the International Ultraviolet Association (IUVA), the Centre for Water Research (CWR) at the National University of Singapore (NUS), China UV Association (CUVA) and Water Industry Division, and China Civil Engineering Association (CCEA), took place on July 7-8, 2025, at NUS.