Key-words: Pacifastacus leniusculus, Procambarus clarkii, desiccation survival, invasive species, dispersal The signal crayfish, P. leniusculus and the red swamp crayfish, P. clarkii are two invasive crayfish species with widely world distribution, being both present at Iberian Peninsula. In this work we study the desiccation survival capacities of both species at 24 ◦ C. Our results showed that both species are capable of surviving exposure to air for long periods of time, with an LT90 of 17.6 and 21.5 h, respectively, for red swamp crayfish and signal crayfish. Our findings are in accordance with the great overland dispersal capacities attributed to these crayfish species.