A method, system, and/or computer program product enables the sharing of memory among mobile devices. Copies of a same hard key holder are installed in all mobile devices from a user-defined group of mobile devices. The hard key holder controls memory sharing between a master mobile device and a slave mobile device. A memory appropriation request is sent from the master mobile device to the slave mobile device. In response to the slave mobile device receiving the memory appropriation request, an unused sector of the memory in the first slave mobile device is reserved for use by the master mobile device. Upon storing of data sent from the master mobile device, a message is sent from the slave mobile device to the master mobile device describing how much room is still available for the master mobile device to use.