Results/Conclusions Zones within caves differed in perceived visibility but these differences did not correlate with differences in temperature or with relative humidity. Overall temperature was negatively correlated with relative humidity but this association was weak. Two caves presented unusually high temperature values and these caves also presented significantly higher arthropod counts. Temperature was only positively correlated with arthropod diversity but the role of temperature on abundance can not be discarded given that diversity and abundance are highly correlated. More species were captured in the April than in the October census but these tendencies were not consistent with temperature or relative humidity differences between censuses Our pooled samples yielded 5,922 soil cave specimens that included 41 morphospecies distributed among 17 orders. Hemiptera (67%), Acari (48%), and Isopoda were the most dominant orders in all caves. The dominance of Hemiptera at these cave systems is a departure from what has been reported in well-studied caves around the world and future studies should focus on their role as potential indicators of change in cave systems of Puerto Rico. Scientific information and local awareness of cave inhabiting species in Puerto Rico is extremely limited. The digital photographs produced by this work can be an important contribution to local biodiversity conservation efforts of these systems.