Oman has a limited resources of fresh water mainly underground water. To preserve those resources and to meet the increase in the fresh water demand, the country turned to water desalination which is known to be very costly and harmful to the environment. Water desalination using solar energy is an attractive alternative for countries like Oman which has a sunny weather all year round and where the length of the day time ranges between 11 to 14 hours. Furthermore, solar energy is a clean source of energy. The aim of the present study is to (1) design and test the solar water still for Omani climate, and (2) to investigate the effect of different design parameters on the still thermal performance.