Portugal’s famous coastline consists of hundreds of miles of sandy beaches. It’s no surprise that urbanisation in the region – a result of tourism and fishing activities – has led to the accumulation of marine litter in these areas. But while local organisations focus their efforts on beach cleaning to keep tourist spots looking pristine, nearby sand dunes accumulate plastics, from plastic bottles to octopus fishing pots. The sand dunes are important ecosystems for insects, birds and plantlife, and generally considered too delicate to census on foot. In Coimbra, Portugal, an interdisciplinary team of scientists is using drones to tally and identify marine litter on local beaches, to understand its origins, and propose methods of protecting these delicate ecosystems.