Abstract The localization of devices is a key ingredient of Internet of Things (IoT) which may requireextra cost for deploying anchor nodes aware of their position. In this work, we propose a range-free localization algorithm, called Drone Range-Free (briefly, Drf ), that replaces the anchor nodes with an off-the-shelf drone. When the radio communications are isotropic, our algorithm localizes the IoT devices ensuring the level of precision required by the final user. However, since an isotropic antenna that propagates its signal in a perfect sphere does not exist in reality, we face a more realistic scenario by proposing an enhanced version of our localization algorithm, called Drone Range-Free Enhanced (briefly, DrfE ), that well tolerates high degrees of irregularity of the antenna signal. Under the anisotropic model, Drf and DrfE exceed in precision all the computational-light previous known range-free localization algorithms based on a mobile rover.