Ocean offers an inexhaustible source of water which is not consumable by humans due to its high salinity. Large amounts of energy are required for desalination, and producing it from fossil fuels can cause harm to the environment. As such, solar energy can be used as an alternative energy source to provide cheap consumable water. This paper aims to investigate the effects of design parameters on single slope solar still evaporation rate under Malaysian conditions. Single sloped solar stills, with varying evaporator basin thickness and condenser plate thickness at different separator heights, were fabricated and tested. The 0.5 mm evaporator basin thickness still set has the highest evaporated volume (250 ml), with evaporation percentage of 25%, while the set with a 1 mm evaporator basin thickness has the lowest evaporation percentage (5.65%) with 56.5 ml evaporated volume. Experimental results indicate that the single slope solar still evaporation rate is very much influenced by climate parameters, namely solar intensity and ambient temperature.