There is limited information about sexual behavior among older Africans, which is problematic given high HIV rates among older adults. We use a population-based survey among people aged 15-80+ to examine the prevalence of sexual risk and protective behaviors in the context of a severe HIV epidemic. We focus on variation across the life course, gender and HIV serostatus to compare the similarities and differences of young, middle aged, and older adults. Younger adults continue to be at risk of HIV, with potential partners being more likely to have been diagnosed with an STI and more likely to have HIV, partner change is high, and condom use is low. Middle aged and older adults engage in sexual behavior that makes them vulnerable at older ages, including extramarital sex, low condom use, and cross-generational sex with people in age groups with the highest rates of HIV. We find insignificant differences between HIV positive and negative adults' reports of recent sexual activity. This study provides new information on sexual behavior and HIV risk across the life course in rural South Africa to inform HIV prevention and treatment programing.