Today's unstable labor market increasingly requires flexibility and adaptability to cope with the threat of unemployment. It can cause distress in people and have a more significant negative impact on fragile workers, such as migrants. This study aimed to test whether a Career Counseling intervention designed for Migrants (CCfM) can develop Career Adaptability and, therefore, both Work Self-efficacy (WSe) and Job Search Self-efficacy (JSSe) perceptions. It was conducted in Italy and involved a sample of 233 migrants, who were asked to respond to a questionnaire available in three languages (Italian, French, and English). Data analysis showed that an improvement was demonstrated in all the variables considered, namely career adaptability (including concern, control, confidence, and curiosity), WSe, and JSSe, even though the CCfM was not directly designed to increase the last one. In addition, the development of career adaptability explained the increase in migrants' WSe and JSSe, and the initial level of career adaptability was found to explain the increase in WSe due to the initial positive level of curiosity.