The dynamics of unauthorized border-crossing in the Mediterranean region has received extensive media coverage but little academic attention. This article examines the patters and dynamics of transit migration towards the Spanish-African borders, and of unauthorized migration across these borders. The geography of migration is examined in detail, and this leads to several conclusions with implications for migration management. First, the origins of sub-Saharan African transit migrants in Morocco are remarkably diverse. Second, cities and towns far beyond Europe play a pivotal role in the migration dynamics at the Spanish-African borders. Third, the Strait of Gibraltar itself has lost much of its importance as a crossing point. Fourth large-scale smuggling to the Canary Islands directly from West Africa is still marginal in numerical terms, but represents a worrying scenario.