A method and system for data session establishment from a mobile device in a multiple networks scenario, the method including, checking whether an identifier for an first network is on a blacklist on the mobile device; if the first network identifier is not on the blacklist, attempting to establish a data connection with the first network; and if the first network identifier is on the blacklist, establishing a data connection with a second network. The method and system for data session establishment include deriving and maintaining the blacklist.