Simulations of three different types of solar stills were performed to compare their productivity using typical meteorological year data of a remote location (Marmul) in Oman. These are the regenerative, conventional, and still with double-glass-cover cooling. Several system parameters were also investigated with respect to their effect on the productivity, namely, water with and without dye in the lower basin, basin heat loss coefficient, mass of water in the basins, and mass flow rate into the double-glass cover. The regenerative still had more than 70% higher productivity in comparison with the conventional still. If the stills are appropriately insulated, the conventional still had higher productivity than the double-glass-cover cooling. Increasing the water in the lower basin moderately reduced the productivity of the three stills. Increasing the water film thickness on top of the lower glass had no effect on the productivity of the still with double-glass-cover cooling, but slightly lowered the productivity of the regenerative still.