For the first time, results are presented from studies using magnetic resonance imaging techniques to follow the behaviour of single water droplets evaporating from porous surfaces. The droplets are initially embedded in the porous substrate by impingement, and are then evaporated over a period of several hours, the surface of the substrate being ventilated by a controlled airflow. The configuration is intended to mimic the behaviour of droplets evaporating into atmospheric flows from surfaces such as sand, or concrete. The method produces several types of data, including images of impinged droplets inside the porous substrate and their development with time during the evaporation episode, one-dimensional concentration profiles through the substrates, and corresponding estimates of the mass fraction of liquid remaining, evaporation rate and mass flux per unit area. The results obtained show that the impinged droplet resides in the porous medium in a shape similar to a semi-spheroid. The results also indicate that the transport of liquid by capillary diffusion has a very strong influence upon the evaporation process, providing a challenge to the simple receding evaporation-front assumption that is utilised in many modelling procedures.