This paper investigates the issues related to the link quality estimation and routing performance in highly dynamic WBSNs, where the inherent body mobility introduces frequent time and space variations in the observed link reliability and network connectivity. A new Opportunistic and Mobility Aware Routing (OMAR) protocol is proposed, which optimizes the routing process by taking benefit from captured long-term and short-term link behavior. Extensive simulations are performed using realistic WBSNs mobility and channel modeling, and representative MAC constraints. The obtained results show that the proposed OMAR approach outperforms conventional routing protocols in terms of energy consumption and routing path length, while ensuring a stable packet delivery ratio.