Ocean gliders are autonomous underwater vehicles, primarily propelled by changes in their buoyancy, with the ability to be piloted remotely. Over the past 25 years gliders have progressed from experimental vehicles through scientific instruments to operational tools. Observations from gliders are now enhancing our understanding of physical, biogeochemical, and biological oceanographic processes. They represent a mature technology and complement traditional ocean sampling capabilities, especially for sustained real-time oceanographic measurements. They are now used as standard research tools in sustainable ocean observations and process studies, collecting measurements of physical, chemical, and bio-optical ocean variables. Underwater gliders have unique capacities to connect open-ocean and coastal processes and to sample the ocean at regional scales during multi-month missions. Gliders have been routinely deployed to monitor the ocean, for example monitoring continental shelves, boundary currents, and polar regions including in under-ice operations. More recently gliders have contributed to environmental hazard detection such as in the detection of marine heat waves and hurricane prediction.

This special issue has been stimulated by the International Underwater Glider Conference (IUGC) that was held in Gothenburg in June 2024, but submissions are open to everyone regardless of participation in the conference. The issue includes papers advancing knowledge on the ocean's physical, biogeochemical, and ecosystem properties and processes by using underwater gliders and/or by their combined use with other observing platforms or numerical models.

Review process: all papers of this special issue underwent the regular interactive peer-review process of Ocean Science handled by members of the editorial board as well as guest editors designated by the OS co-editors-in-chief.