BACKGROUND: Structural, interpersonal and individual level factors can present barriers for HIV prevention behaviour among people at high risk of HIV acquisition, including women who sell sex. In this paper we document the contexts in which women selling sex in Kampala meet and provide services to their clients. METHODS: We collected qualitative data using semi-structured interviews. Women were eligible to participate if they were 18 years or older, self-identified as sex workers or offered sex for money and spoke Luganda or English. Ten women who met clients in venues and outdoor locations were selected randomly from a clinic for women at high risk of HIV acquisition. Ten other women who met clients online were recruited using snowball sampling. Interviews included demographic data, and themes included reasons for joining and leaving sex work, work locations, nature of relationships with clients and peers, interaction with authorities, regulations on sex work, and reported stigma. We conducted interviews over three months. Data were analysed thematically using a framework analysis approach. The coding framework was based on structural factors identified from literature, but also modified inductively with themes arising from the interviews. RESULTS: Women met clients in physical and virtual spaces. Physical spaces included venues and outdoor locations, and virtual spaces were online platforms like social media applications and websites. Of the 20 women included, 12 used online platforms to meet clients. Generally, women from the clinic sample were less educated and predominantly unmarried, while those from the snowball sample had more education, had professional jobs, or were university students. Women from both samples reported experiences of stigma, violence from clients and authorities, and challenges accessing health care services due to the illegality of sex work. Even though all participants worked in settings where sex work was illegal and consequently endured harsh treatment, those from the snowball sample faced additional threats of cybersecurity attacks, extortion from clients, and high levels of violence from clients. CONCLUSIONS: To reduce risk of HIV acquisition among women who sell sex, researchers and implementers should consider these differences in contexts, challenges, and risks to design innovative interventions and programs that reach and include all women.