Method for operating a mobile station being in a radio environment comprising a plurality of radio cells (11, 12, 13) of a plurality of mobile communication networks (100, 200, 300), each one of these radio cells (11, 12, 13) being associated, respectively, to at least one mobile communication network of the plurality of mobile communication networks (100, 200, 300), wherein, as a primary connection of the mobile station, the mobile station is connected to, or registered on, a first mobile communication network of the plurality of mobile communication networks (100, 200, 300) and is, additionally and as a secondary connection of the mobile station, able to be connected to, or registered on, a second mobile communication network of the plurality of mobile communication networks (100, 200, 300), wherein the mobile station is connected to, or registered on, the first mobile communication network as a result of a primary network selection process that is performed taking into account the radio environment as well as network selection data being stored in a memory module of the mobile station, wherein at least part of the network selection data relate to or indicate the first mobile communication network, wherein the network selection data comprise lists or list entries as primary network selection data regarding the primary connection of the mobile station, the primary network selection data being used, by the mobile station, during the primary network selection process, the primary network selection process resulting in the mobile station being connected to, or registered on, the first mobile communication network, wherein, in order for the mobile station to be additionally connected to, or registered on, the second mobile communication network, the method comprises the following steps: -- in a first step, the mobile station comprises or receives secondary network selection data regarding the secondary connection of the mobile station, the secondary network selection data being related, at least in part, to the first mobile communication network and indicating at least the second mobile communication network, wherein the secondary network selection data are also part of the network selection data, wherein specific parts (252', 252") of the secondary network selection data are assigned to the primary network selection data with each specific part (252', 252") corresponding to one of the mobile communication networks selectable as the first mobile communication network, -- in a second step, the mobile station is connected to, or registered on, the second mobile communication network - in addition to being connected to, or registered on, the first mobile communication network - as a result of a secondary network selection process being performed taking into account the radio environment as well as the specific part (252', 252") of the secondary network selection data that corresponds to the first mobile communication network. -- in a first step, the mobile station comprises or receives secondary network selection data regarding the secondary connection of the mobile station, the secondary network selection data being related, at least in part, to the first mobile communication network and indicating at least the second mobile communication network, wherein the secondary network selection data are also part of the network selection data, wherein specific parts (252', 252") of the secondary network selection data are assigned to the primary network selection data with each specific part (252', 252") corresponding to one of the mobile communication networks selectable as the first mobile communication network, -- in a second step, the mobile station is connected to, or registered on, the second mobile communication network - in addition to being connected to, or registered on, the first mobile communication network - as a result of a secondary network selection process being performed taking into account the radio environment as well as the specific part (252', 252") of the secondary network selection data that corresponds to the first mobile communication network.