A mobile wireless communications device may include a plurality of antennas, a plurality of wireless transceivers, and signal processing circuitry. The device may further include a controller for selectively switching the signal processing circuitry to a desired one of the wireless transceivers, and for selectively switching a desired one of the antennas to the desired one of the wireless transceivers. Moreover, the controller may also be for selectively connecting and disconnecting the at least one other one of the antennas to an unused one of the wireless transceivers.