How can scientists uncover the movements and habitat use of aquatic animals? On land, GPS is useful, but that doesn’t work in water. So how can we track animals underwater? One way to do that is using acoustic telemetry. This video demonstrates how that technology works and why it’s useful for the sustainable conservation and management of aquatic life. The creation of this video was supported by the European Tracking Network COST-Action (CA18102). COST (European Cooperation in Science and Technology) is a funding agency for research and innovation networks. Our Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation (www.cost.eu). Translations: German by Florian Stein; Czech by Marie Prchalová; Hebrew by Renanel Pickholtz; Greek by Argyrios Sapounidis; Turkish by Tugce Sensurat; Dutch by Charlotte Steendam; Polish by Arek Duda; Arabic by Sara A. A. Al Mabruk; Portuguese by David Abecasis; Serbian by Marija Smederevac.