This paper examines the relationship between indicators of mobility, socio-economic vulnerabilities, and HIV risk behaviours among 5,498 mobile female sex workers (FSWs) living in the four high HIV prevalence states in India. Female sex workers with greater degree of mobility reported significantly more often than the FSWs with lesser degree of mobility that they experienced physical violence, and consumed alcohol prior to sex. Further, FSWs with greater degree of mobility reported significantly more often than the FSWs with lesser degree of mobility that they had inconsistent condom use in sex with clients, even after controlling for several demographic characteristics and socio-economic vulnerabilities including experiences of violence. Additionally, short duration visits and visit to the Jatra (religious fairs) places found to have significant association with their inconsistent condom use in sex with clients as well as continuation of sex despite having STI symptoms. These findings suggest the need for screening FSWs for higher degree of mobility and to mobilize them to form community networks so as to deal with violence, reduce alcohol use and promote consistent condom use along the routes of mobility. HIV prevention interventions aimed at FSWs require an increased attention to address the socio-economic vulnerabilities including alcohol use, with particular emphasis on those FSWs who are on the move in India and elsewhere.