The community of organisms associated with the red king crab was studied in Dalnezelenetskaya Bay (Barents Sea). A total of 39 taxa of associated organisms were found on 62.9% crabs. Among fouling organisms the hydrozoan Obelia longissima (Pallas, 1766) and the bivalve mollusk Mytilus edulis L., 1758 were the most frequent, while the most common symbiotic organisms were the amphipods Ischyrocerus anguipes Krǿyer, 1838 and Ischyrocerus commensalis Chevreux, 1900, and the copepod Tisbe furcata (Baird, 1837). Copepods had not been previously recorded from the crabs in the study site. Their presence is associated with seasonal aspects of the population development of the common red king crab symbiont I. commensalis, which may displace copepods through competition or predation. The seasonal differences detected in the localization patterns of the symbiotic amphipod I. commensalis are associated with their reproductive oscillations and differences in the population structure. The sex of the crabs did not affect the host colonization patterns, whereas the crab size and molting stage significantly affected the indices of infestation (total prevalence, and both prevalence and mean intensity of common species).