The study of drilling predation has been largely limited to molluscs. Herein, we report drilling predation on Recent acorn barnacles by gastropods from Chandipur, eastern India. The aspects of predator-prey relation dealt here are the size and site preference of the predator; the interrelationship between barnacle shell morphology (e.g., shape, external ornamentation) and drilling intensity; and influence of substrate type on body size and shape of barnacles, as well as predation pressure on it. The study reveals that, barnacles are drilled by the naticid gastropods, which is otherwise an uncommon interaction. Drilling intensity on the barnacles attached to a semi-infaunal bivalve, Timoclea imbricata, is exceptionally high and is comparable to the drilling intensity on the host bivalve. Otherwise, predation pressure is very low on barnacles, supporting previous literature. The study implies that unique live-live associations can create opportunities such that even an unusual predator (e.g., Naticidae) can successfully feed on a novel prey (e.g., barnacles), suggesting dietary opportunism. Studies dealing with the fossil record of drillholes should consider these different ecological (e.g., prey selectivity by the predator, host selection by the epizoan, role of unusual predator on an uncommon prey) aspects of drilling predation on barnacles through space and time. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.