The IEEE OES international symposium on Underwater Technology 2019 (UT’19) organized by IEEE Oceanic Engineering Society (IEEE/OES), IEEE/OES Japan Chapter, IEEE/OES Taipei, Taiwan Chapter, Taiwan Ocean Research Institute, and National Sun Yat-sen University, was held during 16-19 April 2019 at the International Building of National Sun Yat-sen University (NSYSU) in Kaohsiung.