A total of 249 Japanese nationals--tourists (n = 107), students (n = 98), and temporary workers (n = 44)--were recruited at the targeted community venues in Honolulu, Hawaii, and completed a structured survey questionnaire. Reported lifetime sexually transmitted diseases, or STDs infection (10% male and 20% female participants), and HIV infection rates (7%, 2 out of 31 persons tested) were high. Male participants were more likely to practice safe sex with female sex workers than with steady and casual female partners both in Japan and Hawaii. More than 80% of the participants reported having had sex under the influence of alcohol. Multivariate analysis revealed that positive attitudes toward drug use and negative attitudes toward condom use were significantly correlated with the frequency of sex under the influence of drugs with steady partners in the past 12 months. Future HIV/STD prevention intervention programs must target Japanese youths who are planning to visit Hawaii or elsewhere abroad, as well as Japanese high-risk groups (e.g., temporary workers in Hawaii), and provide information about HIV/STD prevention in relation to substance use.