Water snakes of the genus Helicops have different uses of food resources that can facilitate species coexistence. To assess diet and foraging habitat of water snakes in eastern Brazilian Amazonia, we used prey consumed by Helicops angulatus, Helicops hagmanni, and Helicops polylepis deposited in scientific collections to analyze variations in composition, breadth, and niche overlap on a regional scale. Among these prey, we used fish (main item) to calculate ecomorphological attributes that might indicate fish habitat and, consequently, the foraging habitat used by snakes. Our analyses indicate these three snake species have similar diet compositions but differ in the proportion in which each item is consumed. Helicops angulatus had the most generalized diet and H. hagmanni had the most specialized diet. Food niche overlap among the three species was moderate. All three species forage in the medium and upper strata of the water column in the lentic zone; however, H. polylepis feeds on prey with varied morphological features that may indicate foraging in many types of environments. The snakes have similar diets and foraging habitats; however, they use food items and space in different proportions.