The mobility of smart and connected devices in Internet of Things brings the challenge of reliable data forwarding. In this work, a relay-node selection method is proposed for mobility-tolerant data forwarding. The proposed relay-node selection method uses the connectivity information in time-varying networks. The connectivity information of IoT devices is modelled using homogeneous Poisson point processes. The connectivity duration information of all the devices with their neighbours is updated continuously. Based on connectivity information, an optimal relay-node is selected as a data forwarding node. The online relay-node selection from a source node to the base station establishes a data forwarding path. The proposed method selects the relay-nodes based on joint optimization of two network parameters, data latency and packet loss risk. The simulation results show that the proposed method significantly improves the data latency and the packet loss risk for data forwarding over time-varying IoT networks.