Getting reliable geophysical and geological 3D models of the subsurface is an absolute necessity for successful resources exploration. Here, we show how novel UAV-borne geophysical mapping can be extremely valuable for mapping potential new exploration areas that are difficult to access by foot, such as hard rock inter-tidal zones and boulder beaches. We show the results from a multidisciplinary geophysical campaign of highly magnetic dikes and granites along a boulder beach in Brittany, France. Our mapping is carried out using customized geophysical sensor systems with high quality sensors. These include in particular a special designed UAV-towed magnetometer bird and multispectral system for large area mapping purposes. The UAV-borne mapping is supplemented by ground-based gamma-ray spectrometry data and ground-based magnetic gradiomety data. The results clearly demonstrate the value of UAV-borne systems in difficult areas as compared to traditional mapping methods as well as the value of combining various geophysical sensors for exploring the economic geology. All UAV-borne data were collected during two days, while the ground-based data – covering only the inner and dry part of the beach - were collected over seven days.