During September 2014, preferences (in situ) shell type specimens, of hermit crabs in Punta Pajarito, Managed Resources Wetland Area Gulf of  Montijo  (Veraguas) and El Retén beach,  Parita bay (Herrera) panamanian Pacific were analyzed. It is reported that hermit crabs have a greater preference for the shells of Naticidae family, possibly because this is the most abundant in the area shell. 28 individuals from the Diogenidae family were collected at the beach of El Retén, parameters such as individual weight, weight and volume of the shell were taken. When applying the Spearman correlation coefficient to the variables individual weight and weight-volume ratio of the shell, there is no evidence of a correlation between the weight of the organism and the weight-volume relationship of the shell (p = 0.386), so the availability of shells is the parameter that best explains the occupation of shells at El Retén beach. This research constitutes a first effort in the area and allows a basic knowledge of the ecological patterns that interact in the selection of shells by hermit crabs