Background: Homelessness and housing instability in the host countries are central features of the experience of migration to the EU. Although migrant women across the EU encounter obstacles in accessing healthcare services, little is known on the health and access to healthcare services for unstably housed migrant women. The DSAFHIR project aims to better describe the risks faced by migrant women in situations of administrative and social vulnerability, to analyze the barriers to access healthcare and to test specific health interventions. Methods: The DSAFHIR project consists of a two-wave mixed-method survey and the implementation of two tailored sexual health interventions. 474 migrant women aged 18 to 77 years housed in social hotels were surveyed at inclusion. After the implementation of sexual health interventions, respondents were contacted for the follow-up survey (n=284). Discussion: The project provides needed data on migrant women’s health and healthcare access, including non-French speakers. It allows to draw lessons on feasibility and acceptability of quantitative and qualitative surveys on this hard-to-reach population. A high response rate in both waves of the survey (84% and 85%) suggests good acceptability. The attrition is comparable to other migrant longitudinal surveys (60% of the original sample completed the follow-up survey, or 40% of attrition), suggesting that relying on cell phones is possible for follow-up even in contexts of housing instability.