The present study describes some activity patterns in the field and laboratory of five hermit crab species (Calcinus latens, Clibanarius signatus, Clibanarius longitarsus, Diogenes costatus and Diogenes pallescens) inhabiting an intertidal flat of mangrove swamp at Red Sea coast. The recorded activity patterns were clustering, scattering, locomotion, standing up at sediment surface with legs outside the shell, retracted into the shell, feeding, fighting and burying. Among species there was an evident variation in activity patterns. In the field, mono- and dispecific clusters occurred and were composed only by individuals of C. latens and C. signatus. Other three species displayed scattering behaviour. In the laboratory experiment, all five species showed clustering behaviour with different degrees except of C. longitarsus. Experimentally, there was no difference in the recorded activity patterns among subsequent days of observation period. Pooled data displayed by the five hermit crab species showed insignificant relationships between them. Some activity patterns showed cyclic rhythms regarding day/night periods. Also, analysis of similarity and dissimilarity separated the crabs into four groups, three monospecific groups and one dispecific group containing C. latens and C. signatus.