Abstract Wireless sensor networks are being increasingly used for sustainable development. The task of routing in these resource-constraint networks is particularly challenging as they operate over prolonged deployment periods, necessitating optimal use of their resources. Moreover, due to the deployment in unattended environments, they become an easy target for attackers. In this paper, we propose a hierarchical POMDP based approach to make routing decisions with partial/limited information about the sensor nodes, in a secure and energy-efficient manner. We demonstrate in a large-scale simulation that the approach provides a better energy/packet delivery tradeoff than competing methods, and also validate these conclusions in a real-world testbed.