Desalination could be a sustainable solution for responding to the ever-rising demand for water and the scarcity of freshwater resources. But given the substantial energy consumption of conventional desalination methods, greater use of renewable energies such as solar in this area seems inevitable. This study investigated the effect of placing sand within the basin of a simple basin-type solar still on its performance. For this purpose, two solar stills one with a sand-containing basin and the other without sand, were designed and constructed. The stills were then tested in Sabzevar (latitude: 36.20; longitude: 57.67), Iran, to determine the effect of sand. The tests were carried out over three days in early July 2019 for 13 hours each day. The results showed that the presence of sand within the basin of the still increased its water productivity and thermal efficiency by 21.16%. Considering these results and the low cost and high availability of sand, placing sand inside the basin of the solar still appears to be a good solution to increase its efficiency.