A method for establishing a roaming connection via a network access entity of a visited communication network comprising the following steps: transmitting a registration request from a communication terminal to a network access entity of the visited communication network via a first dedicated communication interface which is already established between the communication terminal and the network access entity, wherein the registration request comprises an identification, UE ID, of the communication terminal; interrogating user specific registration data of the communication terminal through the network access entity via a second dedicated communication interface with a home communication network of the communication terminal for receiving user-specific data of the communication terminal from a database of the home communication network of the communication terminal or from an external database based on the UE ID of the communication terminal, wherein the second dedicated communication interface is specifically configured for the roaming, and wherein the network access entity of the visited communication network is connected with the database of the home communication network of the communication terminal via the second dedicated communication interface; transmitting network access data for the access of the communication terminal to the visited communication network through the network access entity to the communication terminal via the first dedicated communication interface based on the user-specific registration data of the communication terminal, wherein the network access data show capabilities of the visited communication network; and establishing the roaming connection by the communication terminal via the visited communication network based on the network access data, wherein the method is carried out in a system comprising the communication terminal, the visited communication network and the home communication network. transmitting a registration request from a communication terminal to a network access entity of the visited communication network via a first dedicated communication interface which is already established between the communication terminal and the network access entity, wherein the registration request comprises an identification, UE ID, of the communication terminal; interrogating user specific registration data of the communication terminal through the network access entity via a second dedicated communication interface with a home communication network of the communication terminal for receiving user-specific data of the communication terminal from a database of the home communication network of the communication terminal or from an external database based on the UE ID of the communication terminal, wherein the second dedicated communication interface is specifically configured for the roaming, and wherein the network access entity of the visited communication network is connected with the database of the home communication network of the communication terminal via the second dedicated communication interface; transmitting network access data for the access of the communication terminal to the visited communication network through the network access entity to the communication terminal via the first dedicated communication interface based on the user-specific registration data of the communication terminal, wherein the network access data show capabilities of the visited communication network; and establishing the roaming connection by the communication terminal via the visited communication network based on the network access data, wherein the method is carried out in a system comprising the communication terminal, the visited communication network and the home communication network.