The localisation algorithms for the WSNs can be divided into range-free and range-based algorithms based on whether it is required to know the actual distances between the nodes or the distance is approximated based on the connectivity information. The range-free algorithms usually have higher localisation error compared to the range based algorithms but it is simple to implement. DV-hop is a typical range-free localisation algorithm employing hop-distance estimation. In this paper, we present three improved DV-hop localisation approaches based on imperialist competitive algorithm (ICA-DV-hop), gravitational search algorithm (GSA-DV-Hop) and inclined planes system optimisation (IPO-DV-hop). In other words, the localisation optimisation problem is solved using the heuristic algorithms to enhance the localisation results of DV-hop. The proposed approaches have been compared with particle swarm optimisation (PSO), genetic algorithm (GA) and original DV-hop method. The simulation results indicate that the proposed algorithms can reduce the localisation error and achieve higher positioning accuracy.