Mobility management in IEEE 802.15.4/ZigBee networks is not efficiently handled. This paper presents an enhanced approach for mobility management of end devices in IEEE 802.15.4/ZigBee cluster tree network related to a backbone network. This approach anticipates link disruption and does not require scanning neighbor cells. It is based on the link quality indicator (LQI) and uses a speculative algorithm. Using different mobility models and network parameters, it is demonstrated that the energy consumption as well as the latency of mobile devices can be significantly reduced.