Background Despite the relatively low prevalence of HIV/AIDS in Korea, the incidence of HIV is steadily increasing, centering on same-sex sexual contact among men in their 20s and 30s. However, in Korean society, where acceptance of homosexuality is low, LGBTQ + research is lacking and there is little empirical data on HIV transmission. This study explored the context in which anal intercourse occurs among male sexual minorities in Korea. Methods Data were collected by conducting a web survey targeting paid members of Korea's largest homosexuality portal site (n = 941). The dependent variable was whether anal intercourse was preferred, and the major independent variables were health behavior, health status, and sexual behavioral characteristics. Results Those who reported that their gender identity was homosexual tended to prefer anal sex more than those who reported that they were bisexual (Chi-square = 5.165, p <.05). For homosexuals that had more unprotected sex (OR = 1.538, 95% CI = 1.281-1.847), had a primary sex partner (OR = 1.943, 95% CI = 1.345-2.809), and had been diagnosed with an STD (OR = 2.978, 95% CI = 1.592-5.568), there was a high possibility of preferring anal intercourse. Bisexuals were more likely to prefer anal intercourse if they had unprotected sex (OR = 1.715, 95% CI = 1.322-2.225) or had a primary sex partner (OR = 1.927, 95% CI = 1.141-3.257). Conclusions This study found that young non-heterosexual men in South Korea are more likely to engage in condomless anal sex while living with HIV/STDs. As a result, primary partners are at higher risk of infection, and bisexual individuals are more likely to transmit HIV/STDs due to similar sexual contexts.