The riblets are small streamwise aligned micro-grooved geometries (in the order of 100-1,000μm) that can reduce the skin friction of an object. They do so, by interacting with the small scale vortical structures in the near wall region and by altering the flow inside the boundary layer. They are suitable for UAV applications, as they are a passive flow control method with great drag reducing potential. In the framework of the RADAERO project, various riblet geometries are investigated both numerically, using high fidelity CFD methods, as well as experimentally, in a subsonic wind tunnel and in flight tests. The riblets designed for the model UAV, feature a blade-shaped geometry with equal groove spacing and height. They are applied solely on specific pre-identified areas of the UAV’s external surface to maximize their drag reducing potential.