The paper describes the heterogeneity of cross-border workers' mobility policies of enterprises, usually planned with relation to their costs. The different mobility forms have in common the attempt to balance the need to reduce the cost of mobility with the goal to make them more palatable, in terms of social protection and professional perspectives. By the "Chartes de Mobilitè", transnational enterprises define mobility policies, applicable to all workers, trying however to take into consideration different needs. Therefore policies' diversification causes a diversification of various mobile workers. Singular is to be considered the case of the s.c. "Third Country National" (Tcn): a workers characterized not only by mobility, but also by a precarious contract. The most recent policies tend to take care of the spouse of mobile worker and of the professional perspectives when back to the original enterprise, in order to encourage mobility.