ABSTRACT. – The lagoon cockle, Cerastoderma glaucum (Poiret, 1789) usually inhabits small, often isolated, water basins. Dispersal among these basins can take place overland (human mediated) or by migratory birds, when cockles are attached to their bodies. It requires the capacity of the cockle to survive aerial exposure. The time of survival of cockles in air was tested. The LT₅₀ was of 80 h at 15 °C and 43 h at 22 °C. There was no significant difference in survival time neither among size classes, nor between males and females. The similarity between male and female mortality curves and the strong differences between the results coming from two thermal conditions suggest that the experiment was reliable.