Animals improve fitness by choosing when and where to disperse in the environment using sensory cues. In freshwater habitats subject to flood and drought, dispersal can urgently challenge newly hatched fish. Here we manipulated rearing environment and sensory systems to reveal an adaptive sensorimotor strategy for dispersal. If we constrained hatchlings or blocked feedback about motion by simultaneously impairing the lateral line and vision, they gulped air and elevated their buoyancy to passively sail on faster surface waters. In stagnant water, hatchlings then covered more ground with hyperstable swimming, tightly steering based on graviception. In hydrodynamic simulations, these adaptations nearly tripled diffusivity and made dispersal robust to local conditions. Through combined use of three senses, hatchlings adapt their behavior to flexibly and efficiently disperse.