Abstract Underwater Acoustic Sensor Networks (UW-ASNs) consist of stationary sensor devices and Autonomous Underwater Vehicles (AUVs), such as gliders and drifters, equipped with sensors whose mission is to perform collaborative monitoring tasks in the complex and dynamically changing underwater environment. UW-ASNs are envisioned for a broad range of applications such as oceanographic data collection, ocean sampling, offshore exploration, disaster prevention, assisted navigation, distributed tactical surveillance, mine reconnaissance, and enemy vessel detection and tracking. Gliders are energy-efficient AUVs that use hydraulic pumps to vary their volume and generate buoyancy changes that power their gliding. This talk deals with efficient underwater communication and coordination algorithms for building a team of smart gliders that can autonomously perform missions such as adaptive ocean sampling and vessel detection and tracking. For these applications, gliders must possess decentralized swarming capabilities, i.e., distributed algorithms should be used to coordinate their operation by exchanging location and movement information, and to relay monitored data to a surface and/or onshore station. To enable these coordination capabilities, which should require minimal human supervision, gliders need to rely on energy-efficient and reliable wireless multi-hop underwater acoustic communications.