International mobility has become a key requirement in science and technology (S&T) professional career progression. On the one hand, the increasing mobility of women suggests that this may be a way for them to avoid or get away from women-unfriendly working environments. On the other hand, international mobility can present problems for women as they, particularly, have to plan their lives around their professional goals and personal lives. This article addresses the international mobility strategies of women regarding their personal and professional choices. We analyse their motivations to move, the way they manage their lives abroad and the effects of mobility on their lives. The analysis is based on 24 in-depth interviews of highly skilled women working in Spanish S&T sectors. Our main findings show that mobility is a new challenge which may improve women's family lives and professional careers. However, they have to plan carefully their lives on a long-term as well as a daily basis. In this sense, they need strong personal determination and the ability to balance their professional and personal goals. Moreover, their personal decisions depend not only on them as individuals, but also on their partners and families, on wider social values, on the institutional support they enjoy, and on the general public policies which they are affected by.