Activation or update of a subscriber identity module (SIM) via a roaming cellular wireless network by a mobile device includes the mobile device: determining a country of origin associated with a mobile network operator (MNO) for the SIM, determining a current geographic location of the mobile device, and when the current geographic location of the mobile device does not correspond to the country of origin for the MNO associated with the SIM of the eUICC, presenting an option to activate or update the SIM over a local roaming cellular wireless network. When the option is accepted, the mobile device enables a cellular data roaming capability for the mobile device, activates or updates the SIM via the local roaming cellular wireless network, and, after the SIM is activated or updated, disables the cellular data roaming capability for the mobile device.