A network of scientists is currently cooperating within the COST (European Cooperation in Science and Technology) Action named “HARMONIOUS” to promote environmental monitoring strategies using drones (UAS). The action aims to establish harmonized UAS monitoring practices and share advances in the field. It involves 36 partner institutions across multiple countries. The action's working groups focus on data processing, vegetation monitoring, soil moisture, stream monitoring and harmonizing methods. The groups conduct field tests and publish findings to advance the use of UAS techniques for environmental applications.