Provided is a pressure-sensitive adhesive tape for preventing adhesion of aquatic organisms, which can express good adhesion even in water, has good mechanical characteristics, facilitates its peeling operation, can maintain an antifouling effect over a long time period, has a small load on a human body or an environment, has a light weight, can maintain stable quality, and can effectively prevent adhesion of aquatic organisms. The pressure-sensitive adhesive tape for preventing adhesion of aquatic organisms of the present invention includes an antifouling layer, a base material layer, and a pressure-sensitive adhesive layer in the stated order, in which: the antifouling layer includes a silicone resin; the antifouling layer includes an antifouling agent; the antifouling agent essentially includes a silicone oil and a liquid paraffin; and the antifouling agent includes at least one kind selected from a surfactant, a liquid hydrocarbon, a fluorinated oil, and an antimicrobial agent.