The first RegCM4 workshop in Southeast Asia region was held in Manila from 25-29 May 2015 and jointly organized by ICTP, Manila Observatory, Aneteo de Manila University, National University of Malaysia, and MAIRS. This workshop was held in conjunction with the third workshop of SEACLID/CORDEX Southeast Asia held at the same venue from 1-2 June 2015. About 50 young scientists from the Southeast Asia region participated at this workshop. Fundings were provided by ICTP and WCRP.