Background: To date, limited research has been conducted to identify the personal and contextual factors that contribute to women’s entry into the sex industry in China. Methods: The reasons for and factors associated with voluntary entry into the sex industry were explored through in-depth interviews conducted with 38 Chinese women who were held in detention centres for selling sex. Results: Women’s personal accounts reveal that entry into sex work is influenced by life aspirations, family responsibilities and social connections, which facilitate mobility to a new urban environment in which they encounter opportunities and challenges. Findings highlight the complex interactions between individual and contextual factors in relation to women’s entry into sex work. Conclusions: In a rapidly developing country such as China, entry into sex work may appeal to women of low socioeconomic status, particularly young women who have recently migrated to urban areas. For members of this mobile and relatively disadvantaged population, comprehensive social services and support are urgently needed.