This study aimed at surveying recreational scuba divers in order to determine demographic characteristics such as diving certification level and diving times, history of medical illnesses or injuries, and incidence of accidents or risks during underwater diving. For this, the authors contacted the managers of 190 diving clubs, which are listed on an online site called "DiveWeb." Responses were obtained from 87 diving clubs, amounting to a total of 154 completed questionnaires. The authors also visited a 4-day-long "Seoul International Sports & Leisure Industry Show" and collected 168 completed questionnaires from certified divers who visited the show. The collected data were analyzed by SPSS for Windows, version 17.0. We found the following results among 314 divers: 261 (83.1%) were male, and 221 (70.4%) were aged 30 to 49 years; 174 divers (55.4%) had over 5 years of diving experience; average body mass index (24.13) was within normal limits; number of non-smokers (175) was greater than that of smokers (139); 110 (35.0%) divers reported past or present diseases (allergic rhinitis being the most common) or injury history. Risky situations that were encountered by the divers included currents, underwater environment, buddy system complications, and air depletion during diving. Underwater diving is a potentially hazardous activity, but at present, medical examinations or fitness tests are not a prerequisite for certified divers in Korea. To secure the safety of underwater divers, we need to establish policies for medical checkups and fitness tests before the divers begin training or attain certification.