A system comprising a global platform provider network operative to communicate with a plurality of wireless networks each having a network home location register "HLR" and further operative to communicate with a plurality of mobile devices (100, 102, 104), with each of the wireless networks operated by a different carrier, the global platform provider network comprising: a provisioning server having access to a set of international mobile subscriber identities "IMSI" allocated to the global platform provider network by the plurality of wireless networks; a distributed HLR of the global platform provider network to store at least one subscription record of a mobile device of the plurality of mobile devices, the mobile device having a subscriber identity module "SIM" identified by a currently activated first IMSI, the currently activated first IMSI belonging to and allocated by the provisioning server from the set of IMSIs allocated to the global platform provider network, and wherein the distributed HLR of the global platform provider network is realized from a plurality of HLR segments, and wherein the provisioning server is operatively arranged: to receive a notification from the distributed HLR that the mobile device has moved from a first wireless network, the notification triggered by the distributed HLR of the global platform provider network receiving an update initiated from a VLR in a second wireless network into which the mobile device has moved, the second wireless network being different to the first wireless network; following confirmation that an allocation rule is satisfied, to add and activate a second one of the IMSIs in the set of IMSIs of the distributed HLR of the global platform provider network and remove the currently activated first IMSI from the distributed HLR of the global platform provider network; and to send the second IMSI to the mobile device to enable the mobile device to communicate wirelessly in the second wireless network as a local device or a roaming subscriber with a new IMSI; and wherein at least one of the HLR segments is associated with a carrier of one of the plurality of wireless networks, said carrier-associated HLR segment being readable and writable by the provisioning server under an agreement between the carrier and a provider of the system. a provisioning server having access to a set of international mobile subscriber identities "IMSI" allocated to the global platform provider network by the plurality of wireless networks; a distributed HLR of the global platform provider network to store at least one subscription record of a mobile device of the plurality of mobile devices, the mobile device having a subscriber identity module "SIM" identified by a currently activated first IMSI, the currently activated first IMSI belonging to and allocated by the provisioning server from the set of IMSIs allocated to the global platform provider network, and wherein the distributed HLR of the global platform provider network is realized from a plurality of HLR segments, and wherein the provisioning server is operatively arranged: to receive a notification from the distributed HLR that the mobile device has moved from a first wireless network, the notification triggered by the distributed HLR of the global platform provider network receiving an update initiated from a VLR in a second wireless network into which the mobile device has moved, the second wireless network being different to the first wireless network; following confirmation that an allocation rule is satisfied, to add and activate a second one of the IMSIs in the set of IMSIs of the distributed HLR of the global platform provider network and remove the currently activated first IMSI from the distributed HLR of the global platform provider network; and to send the second IMSI to the mobile device to enable the mobile device to communicate wirelessly in the second wireless network as a local device or a roaming subscriber with a new IMSI; and wherein at least one of the HLR segments is associated with a carrier of one of the plurality of wireless networks, said carrier-associated HLR segment being readable and writable by the provisioning server under an agreement between the carrier and a provider of the system. to receive a notification from the distributed HLR that the mobile device has moved from a first wireless network, the notification triggered by the distributed HLR of the global platform provider network receiving an update initiated from a VLR in a second wireless network into which the mobile device has moved, the second wireless network being different to the first wireless network; following confirmation that an allocation rule is satisfied, to add and activate a second one of the IMSIs in the set of IMSIs of the distributed HLR of the global platform provider network and remove the currently activated first IMSI from the distributed HLR of the global platform provider network; and to send the second IMSI to the mobile device to enable the mobile device to communicate wirelessly in the second wireless network as a local device or a roaming subscriber with a new IMSI; and wherein at least one of the HLR segments is associated with a carrier of one of the plurality of wireless networks, said carrier-associated HLR segment being readable and writable by the provisioning server under an agreement between the carrier and a provider of the system.