In this paper, we examine the greenhouse horticulture in Algeria's Sahara, which is one illustrative example of the agricultural transitions that have taken place in North Africa on the new irrigation frontiers created through groundwater use. The entrepreneurial farming systems in the region are characterized by considerable mobility. Geographic mobilities of people, ideas, capital, information, and objects and socio-professional mobilities are intrinsically intertwined, whereby skilled sha-recroppers and laborers move sometimes over hundreds of kilometers, attracted by the opportunities of quick monetary gains and by the opportunities of rapid so-cio-professional upward mobility. This paper analyzes, first the different forms of socio-professional and geographical mobilities associated with the groundwater-ba-sed farming systems in Algeria's Sahara, with a particular focus on mobile young farmers; then focuses on the multiple borders that these young farmers crossed on their trajectory; and their return journey after they quit the Sahara.