A method for inter-standard network roaming is provided. Upon roaming into a visited network, an access terminal may send a location update message that includes its current mobile subscriber identity. A roaming gateway receives the update message and uses the current mobile subscriber identity to determine whether the access terminal should be assigned a new mobile subscriber identity for operation in the visited network. If the current mobile subscriber identity indicates that the access terminal is not using a preferred roaming sponsor for the visited network, then the roaming gateway generates or selects a new mobile subscriber identity associated with the preferred roaming sponsor. The new mobile subscriber identity is securely transmitted to the access terminal which uses it for communications over the visited network thereafter.